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E P A - R 2 - 7 3 - 2 6 9 Juri? 1 9 7 3
P repa red f o r
O F F I C E OF RESEARCH AND MONITORING U. S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D . C . 20460
For sale by the Supenntendent of Documents, U.S. Government Printing Of&x, Washtngton, D.C. 2oun Pnce $2.10 domestic postpaid or $1.76 GPO Bookstore
TREATMENT OF COMPLEX CYANIDE
COMPOUNDS FOR R E U S E OR D I S P O S A L
T h o m a s N . H e n d r i c k s o n D r . L o u i s G . D a i g n a u l t
P r o j e c t #12120 ERF
P r o j e c t O f f i c e r
T h o m a s D e v i n e N e w E n g l a n d B a s i n s O f f i c e , E P A
240 H i g h l a n d A v e n u e N e e d h a m H e i g h t s , M a s s a c h u s e t t s 02194
EPA Review Notice
This r e p o r t has been roviowed b y the U.S. Environmcntal Protection Agency, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Environmental Protection Agency, nor does mention of trade names or commercial products con- stitute endorsement or recommendation for use.
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Coinplcs c y a n i d c s (Lcrl-o-and L c r r i c y a n i d c ) i n i n d u s t r i a l wclstc ]\-atci- c i ' i l u c n t s iniposc a c l i rcc t t h r c a t upoii t h c cnvi ronmcnt . >Ictliods t o r c c o v c r o r d e s t r o y t h e s e compounds werc e v a l u a t c d i n l a b o r a t o r y s t u d i e s . Thc t e c h n i q u e s t c s t c d i n c l u d e e l c c t r o l - y s i s , o z o n a t i o n , c h l o r i n a t i o n and heavy m e t a l i o n p r e c i p i t a t i o n . T h e s t u d y was conduc tcd t o d e t c r m i n e t h e f e a s i b i l i t y o f u s i n g one o r inore of t h e s e mcthods t o r e d u c e t h e c o n c e n t r a t i o n of f e r r i c y a n i d e i n b o t h c o n c e n t r a t e d ( 1 0 , 0 0 0 t o 1 0 0 , 0 0 0 mg/l) and d i l u t e ( 1 0 t o 1 0 0 mg/l) w a s t e e f f l u e n t s .
Numerous a n a l y t i c a l p r o c e d u r e s . w e r e d e v e l o p e d t o enhance t h e a c c u r a c y o f sample a n a l y s i s o v e r t h e c o n c e n t r a t i o n r a n g e s t u d i e d .
F e r r o c y a n i d e can b e o x i d i z e d t o f e r r i c y a n i d e i n o v e r f l o w pho to - g r a p h i c c o l o r p r o c e s s b l e a c h e s u s i n g e i t h e r e l e c t r o l y s i s o r ozone and t h e w a s t e b l e a c h r e c i r c u l a t e d f o r r e u s e i n t h e p r o c e s s . D i l u t e c o n c e n t r a t i o n s o f f e r r i c y a n i d e c a n b e d e s t r o y e d u s i n g ozone o r c h l o r i n e u n d e r p r o p e r c o n d i t i o n s o f t e m p e r a t u r e , pH,
r I and c a t a l y s t a d d i t i o n .
A c o s t a n a l y s i s i s i n c l u d e d f o r a l l methods t h a t were judged a c c e p t a b l e f o r commercial d e m o n s t r a t i o n . C o s t d a t a f o r .each p r o c e d u r e i s b a s e d upon an " a v e r a g e combined" p h o t o g r a p h i c p r o c e s s o r as d e f i n e d i n t h e r e p o r t .
T h i s r e p o r t was s u b m i t t e d i n f u l f i l l m e n t o f P r o j e c t 12120 E 2 F , unde r t h e p a r t i a l s p o n s o r s h i p o f t h e U . S . Envi ronmen ta l P r o t e c t i o n Agency.
Key Words:
Ozone F e r r i c y a n i d e Complex Cyanides P h o t o f i n i s h i n g Wastes Chemical Recovery Waste R e c y c l e P r e c i p i t a t i o n C h l o r i n a t i o n
iii
Section
I.
11.
111.
I V .
V.
VI.
VII.
VIII.
IX.
X.
XI.
t d I
TABLE OF CONTENTS
Dcs c r i p t ion
C o n c l u s i o n s
Recommendations
Introduction
Materials fr Apparatus
Procedures
Discussion of Results
Full Scale Ozone Bleach Regeneration and Waste Destruction Installation-- Berkey Photo
Acknowledgments
References
Glossary
Appendices
Page
1
3
5
1 7
21
39
101
107
109
115
119
V
FIGURES
Numb e 1’ Description Page 15.
1.
2 .
3 .
4 .
5.
6.
7 .
8.
9 .
10.
11.
12.
13.
14.
Bench Top Non-Membrane Electrolysis Cell
ilembrane Electrolysis Cell
Pilot Plant Non-Membrane Electrolysis Cell
23
25 16.
26 17. 27
29
Pilot Plant Electrolytic Cell
Pilot Plant Ozone Regeneration Cell 15.
Laboratory Ozone Generator and Air Preparation System
Pilot Plant Ozonation or Chlorination Cell
30 19.
20.
3 1 21.
33 Precipitation Studies Stirring System
Continuous Flow Centrifugation System 35
4 3 Absorbance Curve for Prussian Blue
Absorbance--Total Fe(CN)6 Concentration from 0.0 t o 1.0 mg/litar at 700 mp
Absorbance-:Total Fe (CN) Concentration from 0.0 to 25 mg/liter at 700 mp
4 4
4 5
Percent Unconverted Ferrocyanide--Percent The0 r e t i ca 1 C onv e r s i on Non- bleno r ane E 1 ec t r o 1 y s is at Various Current Density Ratios 50
Sffect of Current Density Ratio on Conversion of Ferrocyanide to Ferricyanide in an Electro- lytic Cell 5 1
2 2 .
2 3 .
.24.
25
26
vi
Page
23
25
26
27
29
3 0
31
33
3 5
43
4 4
45
50
5 2
x u1:\b c '1'
15. -
16.
17.
18.
19.
20.
21.
22.
23.
.24.
25
26
Dcscription
E f f c c t of Currcnt Dciisity Ratio on Ferrocyanide Oxidation Rate for Non- Ncmbrane Electrolytic Cell
Comparison of the Actual and Theoretical Conversions of Ferrocyanide t o Ferricyanide in a Membrane Type Electrolytic Cell
Current-Temperature Relationship for a Mem- brane Type Electrolytic Cell
Schematic of an Electrolytic Bleach Regener- ation System
Conversion--Time Curve for Ozone Regeneration
Effect of Solution Flow Rate on Ferrocyanide During Pilot Plant Ozonation Studies
Flow Schematic of A Photographic Bleach Re- generation System Using Ozone
Rate of Degradation of Total Fe(CN)6 During Ozone Oxidation Between 70"-90°C
Effect of Temperature on Fe(CN)6 During Acid Ozone Oxidation
Ozone Destruction of Ferrocyanide: A Flow Schematic
Effect of Rotor Speed on Solution Clarizy for Iron Precipitation of Complex Cyanide Using Various Flocculants
Effect o f Rotor Speed on Solution Clarity for Manganese Precipitation of Complex Cyanide Using Various Flocculants
vii
Page
53
5 4
55
5 9
61
6 7
58
72
7 3
7.;
8 4
Numb e r
27.
-
28.
29.
3 0 .
.a
3 1
32
33
34
35
36
37
3 7A
Description Page. Numb - 5
Effect of Rotor Speed on Solution Clarity for Cadmium Precipitation of Complex Cyanide U s i n g Various Flocculants
-
85
Effect of Rotor Speed on Solution Clarity for Copper Precipitation of Complex Cyanide Using Various Flocculants 86
Lficct 0; Aotor Speed on Solution Clarity for zinc precipitation of Complex Cyanide Using Various Flocculants
Effect of Flow Rate on Solution Clarity for Iron Precipitation of Complex Cyanide Using Various Flocculants
Effect of Flow Rate On Solution Clarity for Manganese Precipitation of Complex Cyanides Using Various Flocculants 89 Effect of Flow Rate on Solution Clarity for Cadmium Precipitation Using Various Flocculants. 90 Effect of Flow Rate on Solution Clarity for Copper Precipitation of Complex Cyanides Using Various F1 occul an ts
Effect of Flow Rate on Solution Clarity for Zinc Precipitation of Complex Cyanides Using Various Flocculants 92
Rate of Loss of Ferricyanide During Ambient
Rate of Loss of Ferricyanide During Elevated
Chlorination System: Flow Schematics
Flow Diagram of Bleach Regeneration System
91
Temperature Chlorine Oxidation 94
Temperature Chlorine Oxidation 35
99
100 and Concentrated Waste Oxidation System
3
4
4
viii
e
r z
or
i n t s .
.ns
Zinc . ous
Numb c 1' D e s c r i p t i o n Page4
5s Ozone G e n e r a t i o n and D i s t r i b u t i o n i Systems I n s t a l l e d a t Berkey F i lm
8s'i P r o c e s s i n g P l a n t , F i t c h b u r g , Mass- t e c h u s e t t s fi
Page
102
39 F e r r i c y a n i d e B leach R e g e n e r a t i o n Tanks I 861
u a t Berkey F i lm P r o c e s s i n g P l a n t F i t c h b u r g , f hias s ac hus e t t s 103
1 40 Waste T r e a t m e n t Tanks a t Berkey F i lm P r o - 8 c e s s i n g , F i t c h b u r g , M a s s a c h u s e t t s 105
4 1 P h o t o g r a p h i c S o l u t i o n T e s t i n g S t a t i o n a t Berkey F i l m P r o c e s s i n g P l a n t F i t c h b u r g ,
8 M a s s a c h u s e t t s 1 0 6
F 8 9;
90
j I
I , ix
TABLES
XI I Numb e r
I
11
Analysis of Ferro-and Ferricyanide With Nitro Prusside as an Interfering Ion
IV
V
VI
VI I
VIIi
IX
X
XI
XI IA
XI IB
Page
XI I
Dcscription
Sodium Ferricyanide [Na3Fe (CN) 61 Concentration as Determlned by Iodometric Titration Methods
Sodium Ferrocyanide [NadFe(CN)6* 10 HzO] Concentration as Determined by Cerimetrlc Titration Method
40
41
4 8
Conversion Efficiency of Pilot Plant Non-Membrane Electrolytic Cell
Comparison of Experimental Results , to Stoichiometric Calculations
Results of Bench Top Ozonation of Used Photographic Bleach
Results of Ozone Destruction of Ferro- cyanide at Ambient Temperature
Effect of Initial pH on Ferrocyanide [Fe (CN)6-4] Concentration
Effect of Initial pH on Heavy Metal Ferrocyanide Precipitation Rate
57
63
6 4
77
77
Effect of Excess Heavy Metal on Ferro- cyanide [Fe (CN) 6-41 Solution Concentration 78
Effect of Temperature zn Heavy Sletal Ferrocyanide [Fe(CN)6- ] Concentration 78
Heavy Metal Precipitation of Complex Cyanides f r m Solutions Containing Both Ferro-and Ferricyanide Salts (mg/l ferrocyanide) 79
Heavy Metal Precipitation of Complex Cyan- ides from Solutions Containing Both Ferro- and Ferricyanide Salts (mg/l ferricyanide) 79
X
XXIXA Page i
i XIIIB
40 t
41
48
57
63
6 4
70 j I
Effect of Settling Time 0 0 Fcrrocyanidc Concentration
Effec t o f S e t t l i n g T i m e on Ferricyanide Concontration
Page
80
80
77 i
X i
SNOISfl73N03
I N O I . I . 3 ~ 1 S
SECTION I 1
RECOMMENDATIONS
The r e s u l t s o f t h i s p r o j e c t d e m o n s t r a t e s u c c e s s f u l methods f o r e l i m i n a t i n g t o x i c complex c y a n i d e s from p h o t o g r a p h i c w a s t e waters. S i n c e t h i s compound r e p r e s e n t s a h a z a r d i n t h e f o r m o f t o x i c c y a n i d e i o n , and s i n c e i t i s n o t b i o d e g r a d e d i n munic- i p a l s e c o n d a r y t r e a t m e n t p l a n t s , i t must be t r e a t e d a t i t s sou rce .
The r e s u l t s o f t h i s r e p o r t s h o u l d b e made a v a i l a b l e t o :
- r e g u l a t o r y commit tees e s t a b l i s h i n g chemica l l imits f o r s t r e a m s and s e w e r s ,
- m u n i c i p a l r e g u l a t o r y a g e n c i e s t h a t must b e conce rned w i t h t h e d e p o s i t i o n o f t h e compounds i n m u n i c i p a l s e w e r s ,
- m u n i c i p a l t r e a t m e n t p l a n t o p e r a t o r s , and
- p h o t o g r a p h i c p r o c e s s i n g p l a n t s d i s c h a r g i n g t o x i c complex c y a n i d e s .
S i n c e t h e r e a r e obv ious economic a d v a n t a g e s f o r r e d u c i n g t h e d i s c h a r g e of f e r r o c y a n i d e s , no p l a n t s h o u l d b e a l l o w e d t o con- t i n u e t o dump waste w a t e r s c o n t a i n i n g ha rmfu l c o n c e n t r a t i o n s of t h i s compound.
3
I N T R O D U C T I O N
Thc p u r p o s e o f t h i s i n v e s t i g a t i o n was t o e v a l u a t e e l e c t r o l y t i c and ozone o s i d a t i o n t e c h n i q u e s f o r t h e r e g e n e r a t i o n of f e r r o - c y a n i d e i o n f o r reuse and t o e v a l u a t e o z o n a t i o n , p r e c i p i t a t i o n and c h l o r i n a t i o n f o r t h e t r e a t m e n t o f w a s t e s o l u t i o n s c o n t a i n - i n g complex c y a n i d e s from f i l m p r o c e s s i n g w a s t e d i s c h a r g e s . A maximum r e s i d u a l f e r r o c y a n i d e concen t r a t ion of 0 . 4 mg/l was t h e g o a l e s t a b l i s h e d f o r t r e a t e d w a s t e .
5
TOXICITY O F F E R R O - A N D FERRICYANIDE
F e r r o - a n d f c r r i c y a n i d e compounds c a u s e o n l y s l i g h t s k i n i r r i t a - t i o n on d i r e c t c o n t a c t . t o x i c t o humans. o n l y s l i g h t a c u t e o r c h r o n i c s y s t e m i c t o x i c i t y upon i n g e s t i o n . ( l )
Burd ick and L i p s c h u e t z r e p o r t t h a t , " P o t a s s i u m f e r r o c y a n i d e and f e r r i c y a n i d e have n o t b e e n c o n s i d e r e d a s p a r t i c u l a r l y t o x i c ( t o f i s h ) . " ( 2 ) The t o x i c i t y t o f i s h and o t h e r acquatic l i f e i s r e - p o r t e d t o be d i r e c t l y a s s o c i a t e d w i t h s t r o n g u l t r a v i o l e t i r r a - d i a t i o n , a s f rom s u n l i g h t . ( 3 ) (4) (5) ( 6 )
L u r ' e and Panova ( 7 ) h a v e shown t h a t f e r r o c y a n i d e f i r s t o x i d i z e s t o f e r r i c y a n i d e w i t h a i r i n w a t e r and t h e n p h o t o c h e m i c a l l y oxi- d i z e s t o i r o n h y d r o x i d e , h y d r o c y a n i c a c i d and s i m p l e s o l u b l e c y a n i d e s . The p r o p o s e d mechanism i s :
N e i t h c r compound i s Cons ide red t o b e Both compounds have b e e n r e p o r t e d a s c a u s i n g
O v e r a l l R e a c t i o n :
4 Fe(CN)6-4 + O 2 + 1 4 H 2 0 lp 4 Fe(OH)3 + 1 2 HCN + 4 OH' + 1 2 CN-
They r e p o r t t h a t t h e r a t e o f o x i d a t i o n o f f e r r o c y a n i d e i n t h e p r e s e n c e of s u n l i g h t l e a v e s a b o u t 2 5 % o f t h e o r i g i n a l c r n c e n - t r a t i o n i n f i v e days . . . . . t h e f e r r o c y a n i d e d i s a p p e a r i n g c o m p l e t e l y i n 1 0 - 1 2 d a y s .
A r e c e n t government r e p o r t h a s c o n f i r m e d t h e i n c r e a s e d t o x i c i t y o f complex c y a n i d e s f rom p h o t o g r a p h i c w a s t e s i n t h e p r e s e n c e o f s u n l i g h t . v e r s i o n o f complex c y a n i d e t o v o l a t i l e c y a n i d e ( H C X ) i s p r o b a b l y r e v e r s i b l e and p r o d u c t l i m i t e d . The t e s t i n g was c a r r i e d o u t u s i n g an Ektachrome p h o t o g r a p h i c w a s t e s i m i l a r t o a l l commercial f i l m p r o c e s s i n g f e r r i c y a n i d e b l e a c h e s .
The r e s u l t s o f v a r i o u s t e s t s show t h a t t h e C O A -
The r e p o r t s t a t e s :
"The r e s u l t s of t h i s p r e l i m i n a r y e x p e r i - ment i n d i c a t e t h e c o n v e r s i o n of complex c y a n i d e s t o h i g h l y t o x i c H C N o c c u r s r a p - i d l y and i s o f g r e a t t o x i c o l o g i c a l s i g n i - f i g a n c e when d i s p o s i n g of u n t r e a t e d pho to - g r a p h i c w a s t e . An E A - 4 (Ektachrome pho to - g r a p h i c ) s o l u t i o n of 4 m l / l ( a c o n c e n t r a - t i o n which k i l l e d no f i s h i n 9 6 h o u r s w i t h - o u t s u n l i g h t p r e s e n t ) g e n e r a t e d o v e r 2 2 0
6
s C IT
.-
f I
s i n g i o n . (1)
e and c ( t o s r e - r r a -
i d i zes o x i -
l e
-
i r i t a - I
~ b c $
.2 C N -
E P
c i t y e n- b ab i y t r c i a l
tiiiics tlic LC ( 5 0 ) o f frcc c y n n i t l c ( t a k e n €rolii i Jntcr Q u a l i t y C r i t e r i a , blcKcc a n d IL'olf, 1903; C n l i f o r n i a S t a t c N a t c r Q u n l - i t y C o n t r o l E o n r d a s 0 . 0 5 i n g / l ) i n s i x h o u r s ~ I i c n exposed t o s u n l i g h t . l y , t h e c y a n i d e b l e a c h c a n n o t b e d i s c h a r g e d u n t r e a t e d w i t h o u t t h e r i s k of a ma jo r f i s h k i l l . any c i r c u m s t a n c e s i s n o t recommended." ( 8 )
Obvious-
D i s p o s a l o f u n t r e a t e d b l e a c h u n d c r
Eastman Kodak has " V e r i f i e d t h e conversion t o c y a n i d e i n o u r r a t h e r e x t r e m e e x p e r i - ments w i t h f i s h . A 6 , 0 0 0 - W xenon lamp ws used t o s i m u l a t e s u n l i g h t . The i n t e n s i t y a t t h e s u r f a c e o f t h e a q u a r i a was a b o u t 6 , 0 0 0 f o o t c a n d l e s . p r e p a r e d s o t h a t t h e f e r r i G y a n i d e and f e r r o c y a n i d e were o f t h e o r d e r o f a few hundred m i l l i g r a m s p e r l i t e r . F i s h were p l a c e d i n t h e a q u a r i a w i t h t h e f e r r o c y a n i d e and f e r r i c y a n i d e c o n t e n t a t t h a t r e l a t i v e l y h i g h c o n c e n t r a t i o n . I n e x p e r i m e n t s w i t h - o u t t h e xenon lamp, t h e f i s h l i v e d d u r i n g t h e t e s t p e r i o d j u s t a s d i d t h e f i s h i n t h e s t a n d a r d t a p w a t e r . t h e same 9 6 hour t e s t was r e p e a t e d w i t h t h e xenon lamp i l l u m i n a t i n g t h e a q u a r i a con- t i n u o u s l y , t h e f i s h d i e d . " ( 9 )
B leach b a t h s were
However, when
Xew York i s t h e o n l y s t a t e s p e c i f i c a l l y l i m i t i n g t h e d i s c h a r g e o f complex c y a n i d e s i n t o r e c e i v i n g waters . mg/ l Fe (CN)6.
The l i m i t i s 0 . 4
Due t o t h e c o n v e r s i o n o f complex c y a n i d e s i d e s , t h e complex s h o u l d b e c o n v e r t e d t o t h e e q u i v a l e n t amount o f c y a n i d e ( C N ) and compared t o sewer and s t r e a m l i m i t s f o r t h a t l a t t e r compound. The r a n g e o f s ewer c o d e s f o r c y a n i d e i s 0 . 0 t o 1 0 . 0 mg/l ( 1 0 ) w h i l e t h e r a n g e i n s t r e a m s t a n d a r d s i s 0 . 0 t o 1 . 0 mg / l . These v a l u e s depend upon t h e s p e c i f i c c i t y , s t r e a m , p o i n t o f e n t r y , e t c . b u t r e p r e s e n t a r e a s o n a b l e r a n g e o f c o n c e n t r a t i o n s t h a t c y a n i d e t r e a t m e n t equipment s h o u l d be c a p a b l e o f m e e t i n g F e r r o c y a n i d e (Fe ( C N ) - 4 ) i o n c o n c e n t r a t i o n c a n be c o n v e r t e d t o c y a n i d e (CN') by mu t i p l y i n g t h e f e r r o c y a n - i d e c o n c e n t r a t i o n by 0 . 7 .
t o t o x i c s i m p l e cyan-
P S o u r c e s o f F e r r o c y a n i d e and F e r r i c y a n i d e
The f o l l o w i n g i n d u s t r i e s have b e e n l i s t e d i n t h e Condensed C h e n i c a l D i c t i o n a r y , 5 t h E d i t i o n , 1956 a s users of f e r r o c y a n i d e and f e r r i c y a n i d e . (11)
9
7
1.
3 . 4. 5 . 6 . 7 . 8 . 9.
1 0 .
1 1 , 12, 13.
7 I .
P h 0 t 0 6 1- 3phy C a l i c o P r i n t i n g Kood Dyeing Tempering S t e e l E t c h i n g L iqu id P r o d u c t i o n o f P igments E 1 e c t r op 1 a t i ng L e a t h e r b l anufac tu r ing Paper blanufac t u r i n g S e n s i t i v e C o a t i n g I n g r e - d i e n t on Blue P r i n t Pape r 1'i ;!lll"llts J J Y C i I I ~ 1'r i l i t i ng
1 ~ I ~ I ~ I ~ O ~ ~ ' ~ A N T 1111
1. Pho tography 2 . B luc Pigments 3 . B l u e p r i n t Paper 4. M c t a l l u r g y 5 . Tanning 6 . Dycs 7 . h led ic ine 8 . R e a g e n t s 9 . Dry C o l o r s
1 0 . Tempering S t e e l 11. E x p l o s i v e s 1 2 , J)roc(::.;s 1 ;3~~ ; rav j ng 13, L i t h o g r a p h y
Iiowcver, s i n c e t h e p r i m e c o n t r a c t o r f o r P r o j e c t 1 2 1 2 0 ERF i s 3 p h o t o g r a p h i c p r o c e s s o r , t h e p r i m a r y o b j e c t i v e was t h e r e d u c - t i o n of complex c y a n i d e s from t h i s s o u r c e o f w a s t e e f f l u e n t . The, r e u s e o f any w a s t e depends upon a number o f p a r a m e t e r s , i n c lu3 i 112 s 3 111 t i 011 p u r i t)', chein i c a l , conc en t r a t i o n , t emper a t u r e , eti. S i n c e t h e i r a r i a b l e s i n t h e methods o f complex c y a n i d e r e u s e s t u d i e d were r e l a t e d s p e c i f i c a l l y t o p h o t o g r a p h i c p r o - c e s s i n g a p p l i c a t i o n s , i t i s n o t a n t i c i p a t e d t h a t t h e s y s t e m s recommended f o r t h i s a p p l i c a t i o n w i l l h a v e d i r e c t a p p l f c a t i o n i n o t h e r i n d u s t r i e s .
The s t u d y o f complex c y a n i d e s f o r t o t a l d e s t r u c t i o n i s more i n d e p e n d e n t o f s p e c i f i c i n d u s t r y a p p l i c a t i o n , s i n c e o n l y t h e c o n c e n t r a t i o n and volume o f s o l u t i o n need b e known t o d e s i g n a p r e l i m i n a r y sys t em u s i n g d a t a i n c l u d e d i n t h i s r e p o r t .
The y e a r l y d i s c h a r g e o f f e r r i c y a n i d e s a l t s f rom p h o t o g r a p h i c s o u r c e s h a s been e s t i m a t e d a t 5 , 0 0 0 , 0 0 0 pounds . (12)
F e r r i c y a n i d e i n P h o t o g r a p h i c P r o c e s s i n g h 'as tes
F e r r i c y a n i d e b l e a c h e s a r e found i n c o l o r p h o t o g r a p h i c p r o c e s s i n g a p p l i c a t i o n s ( s e e Appendix F ) , where i t h a s been u s e d a s a s t a n - d a r d b l e a c h i n g a g e n t f o r y e a r s . The f u n c t i o n o f t h e b l e a c h i n t h e p h o t o g r a p h i c p r o c e s s i s t o o x i d i z e t h e m e t a l l i c s i l v e r i n t h e p h o t o g r a p h i c e m u l s i o n t o a s i l v e r h a l i d e . Dur ing t h a t o s i d a - t i o n , t h e f e r r i c y a n i d e and h a l i d e i o n c o n c e n t r a t i o n s o f t h e b a t h d e c r e a s e , w h i l e t h e f e r r o c y a n i d e c o n c e n t r a t i o n i n c r e a s e s . Bromide i o n i s t h e most common h a l i d e i o n . The r e a c t i o n for p h o t o g r a p h i c b l e a c h i n g i s :
- 4 I
Ago + Fe(CN)6-3 + B r ' + AgBr+ + Fe(CN)6
T O t h e TI. 3 f c 1 f o l for. Ph'
SOC (X2
SOC (Ne
SOC (N2
S O (
soc
SOC
1
LC -
, r e ,
n
i n g an - n
i d a - a t h Dmide 3 h i c
TO a i c ~ i n t a i n t h c prope1- c o n c c n t r a t i o n OF' s o l u t i o n c o n s t i t u e n t s , t h e s o l u t i o 1 1 i s c o n s t a n t l y r c p l c n i s l i c d w i t h f r c s h m a t e r i a l . T h a t d i s t i n g u i s l l c s t h c two pr i inary s o l u t i o n s f o r a l l p r o c e s s ins f o r m u l a t i o n s , t h e r c p l e n i s h c r and working t a n k s o l u t i o n s . Thc f o l l o w i n g i l l u s t r a t i o n shows some t y p i c a l c h e m i c a l concentrations f o r a work ing t a n k and a r e p l e n i s h e r t a n k from t h r e e d i f f e r e n t p h o t o g r a p h i c p r o c e s s e s .
EXAMPLE A
BLEACH BATH COMPOSITION
FROM A TYPICAL COLOR REVERSAL PROCE
Sodium F e r r o c y a n i d e (I\ia4Fe (CN) 6' 1 0 H2O)
Sodium F e r r i c y a n i d e - (Na3Fe (CN) 6 )
Sodium Bromide (NaBr)
s4
W O R K I N G TANK ( g / U
4 5 . 0
1 2 0 . 0
25.0
EXANPLE B
BLEACH BATH COMPOSITION
FROM A TYPICAL COLOR NEGATIVE FILM PROCESSOR
WORKING TANK Cg/U
Sodium F e r r o c y a n i d e D e c a h y d r a t e 6 . 0
Sodium F e r r i c y a n i d e 2 3 . 0
Sodium 3 r o n i d e 1 5 . 0
9
REPLENISHER ( g / U
5 . 0
140.0
r s . 0
2.0
26.0
17.0
EXAMPLE c BLEACH BATH COMPOSITION
FROM A T Y P I C A L COLOR POSITIVE PAPER PROCESSOR
WORKING TANK KEPLENI SHER (s/1) ( E / 1)
Sodium F e r r o c y a n i d e D e c a h y d r a t e 1 3 . 0 4 2 . 0
Sodium F e r r i c y a n i d e 1 7 . 0 2 5 . 0
Sodium Bromide 7 .0 8 . 0
The o v e r f l o w b l e a c h f rom t h e work ing t ank i s one s o u r c e o f f e r r o - c y a n i d e w a s t a g e from t h e p h o t o g r a p h i c p r o c e s s . I n a d d i t i o n , as f i l m p a s s e s t h r o u g h t h e p r o c e s s i n g s o l u t i o n s , i t c a r r i e s a ce r - t a i n volume o f t a n k s o l u t i o n t o t h e n e x t t a n k , T h a t c a r r y o v e r i s t h e t o t a l o f t h e s u r f a c e l i q u i d and t h e s o l u t i o n a b s o r b e d i n t o .the f i l m e m u l s i o n . The c a r r y o v e r r a t e depends upon many f a c t o r s , i n c l u d i n g t h e s p e e d of t h e p r o c e s s and t h e p h o t o p r o - d u c t s b e i n g p r o c e s s e d . The c a r r y o v e r l o s s o f s o l u t i o n b l e a c h i n t o t h e n e x t b a t h i n t h e p r o c e s s i s a s e c o n d s o u r c e o f b l e a c h l o s s . The b a t h f o l l o w i n g t h e b l e a c h i s e i t h e r a p h o t o g r a p h i c f i x i n g b a t h o r a wash wa te r .
X l i p r o c e s s i n g l a b o r a t o r i e s a r e i n a p o s i t i o n t o e s t i m a t e t h e ave rage c o n c e n t r a t i o n o f f e r r i c y a n i d e d i s c h a r g e d f rom t h e p h o t o - g r a p h i c l a b o r a t o r y o v e r a s p e c i f i e d p e r i o d o f t ime. T h a t c a n be done by c a l c u l a t i n g t h e pounds o f f e r r o - o r f e r r i c y a n i d e pu rchased and d i v i d i n g by t h e t o t a l volume o f w a t e r u s e d by t h e l a b o r a t o r y d u r i n g t h e same p e r i o d . e v e r y pound o f f e r r i c y a n i d e p u r c h a s e d i.s a t some t i m e l o s t t o t h e sewer. . I f t h e a v e r a g e c o n c e n t r a t i o n i s above s t r e a m o r m u n i c i p a l s ewer r e g u l a t i o n s ( f o r e i t h e r complex o r s i m p l e cyan- i d e s ) , methods o u t l i n e d i n t h i s r e p o r t c a n b e u s e d t o r e d u c e t h e c o n c e n t r a t i o n t o a c c e p t a b l e l e v e l s .
I n t h e p h o t o g r a p h i c l a b ,
S i n c e a l l c o l o r p h o t o g r a p h i c b l e a c h e s c o n t a i n i n g c y a n i d e a r e d i f f e r e n t o n l y i n c o n c e n t r a t i o n by f a c t o r s o f 3 - 5 , t h e s t a t e - ment t h a t Ektachrome b l e a c h e s , " canno t be d i s p o s e d o f w i t h o u t d e g r a d a t i v e t r e a t m e n t . . . . . . . " ( 8 ) would a p p l y t o a l l b l e a c h e s A f u r t h e r s t a t e m e n t f rom t h e same r e p o r t t h a t , "Under no c i r - cumstances may u n t r e a t e d E A - 4 (Ektachrome) b l e a c h b e s a f e l y r e l e a s e d i n t o any s t ream." ( 8 ) would Thus b e a p p l i c a b l e t o t h e f u l l r a n g e o f p h o t o g r a p h i c b l e a c h e s c o n t a i n i n g complex c y a n i d e s .
A d d i x i o n a l i n f o r m a t i o n on t h e p o l l u t i o n p rob lems i n t h e p h o t o - g r a p h i c i n d u s t r y c a n b e found i n t h e Appendices o f t h i s r e p o r t .
The E f e r r : y s i s
Elec' - In t l t h e 1
Anodl
Fe (C;
Cath,
*ZO Fe (C
The t o f t i o n s t u d t h e by a
I n c r c u r r l a t i (C. 0
w =
An i r e a c r e a c a t e pos s w e I t o f o f s t h i s
Wher cyar W i t i c a n
10
R -
I r r o - as r- r
h
t o -
ie
A-
i
THEORETICAL APPROACH
Tlie me thoJs used i n this s t u d y f o r t h e c o n v c r s i o n o f f e r r o t o f e r r i c y a n i d e , o r t l ie d e s t r u c t i o n o f f e r r o c y a n i d e were : e l e c t r o l - y s i s , o z o n a t i o n , c h l o r i n a t i o n , and c h e m i c a l p r e c i p i t a t i o n .
E l e c t r o l y s i s o f F e r r o c y a n i d e
I n t h e e l e c t r o l y t i c o x i d a t i o n o f f e r r o c y a n i d e t o f e r r i c y a n i d e , t h e most p r o b a b l e anode and c a t h o d e r e a c t i o n s a r e as follows:
Anode R e a c t i o n s :
F ~ ( c N ) ~ - ~ -+ Fe(CN)6
&,OH' -+ 1 / 2 02 + H20 + e' ( s e c o n d a r y r e a c t i o n ) E O = - 0 . 4 0 V o l t s (3)
Cathode R e a c t i o n s :
- 3 + e- ( p r i m a r y r e a c t i o n ) E O = - 0 . 4 9 V o l t s ( 2 )
H20 + e- + 1 / 2 H 2 + OH-
Fe(CN)6-3 + e' + Fe(CN)6'4 ( s e c o n d a r y r e a c t i o n ) &' = 0 . 4 9 V o l t s ( 5 )
The o b j e c t i v e of t h i s s t u d y was t h e c o n v e r s i o n of f e r r o c y a n i d e t o f e r r i c y a n i d e . Thus , m i n i m i z i n g t h e s e c o n d a r y c a t h o d e r e a c - t i o n i s mandatory . Two methods o f o b t a i n i n g t h i s r e s u l t were s t u d i e d : i n c r e a s i n g t h e c a t h o d e c u r r e n t d e n s i t y r e l a t i v e t o t h e anode c u r r e n t d e n s i t y , and s e p a r a t i n g t h e e l e c t r o d e s o l u t i o n by a n i o n pe rmeab le membrane.
I n c r e a s i n g t h e c a t h o d e c u r r e n t d e n s i t y ( r e l a t i v e t o t h e anode c u r r e n t d e n s i t y ) i n c r e a s e s t h e hydrogen o v e r v o l t a g e . The re- l a t i o n s h i p f o r i n c r e a s e d o v e r v o l t a g e (w) w i t h c u r r e n t d e n s i t y (C.D.) i s as f o l l o w s :
(p r imary r e a c t i o n ) € 0 = - 0 . 8 2 8 V o l t s ( 4 )
w = a + B l o g (C.D.)
An i n c r e a s e i n hydrogen o v e r v o l t a g e a t t h e c a t h o d e f o r t h i s r e a c t i o n r e s u l t s i n a b u i l d u p o f hydrogen g a s b u b b l e s (p r imary r e a c t i o n ) a t t h e c a t h o d e s u r f a c e , (13) The gas b u b b l e s i n s u i - a t e t l ie c a t h o d e from t h e f e r r i c y a n i d e s o l u t i o n , r e d u c i n g t h e p o s s i b i l i t y o f t h e s e c o n d a r y c a t h o d e r e a c t i o n . Thus , hydrogen O v e r v o l t a g e would r e s u l t i n a n i n c r e a s e i n t h e o v e r a l l f e r r o - t o f e r r i c y a n i d e c o n v e r s i o n . E x p e r i m e n t a l l y , v a r y i n g t h e r a t i o of anode c u r r e n t d e n s i t y t o c a t h o d e c u r r e n t d e n s i t y would show t h i s e f f e c t .
When a c a t i o n permeable membrane i s u s e d t o s e p a r a t e t h e ferro- c y a n i d e from t h e c a t h o d e , t h e c o n v e r s i o n c a n b e i n c r e a s e d . With membranes o f t h i s t y p e , o n l y t h e p o s i t i v e l y c h a r g e d c a t i o n s c a n p r o d u c e a c u r r e n t t h r o u g h t h e membrane. The sodium o r
11
p o t n s ~ i u i i i i o n s i n t h e anoclc chamber p a s s t h r o u g h t h e mcmbranc a n d arc rccluccd a t t h e cathoclc . Uuc t o i t s n c g a t i v e c h a r g e I c r r i i > * n n i d c c a n n o t p a s s t h r o u g h t h e mcmbrane and b e rcduccd t o ferrocyanide. The c l i n i i n a t i o n 01 t h i s r e d u c t i o n p r o c c s s r e s u l t s i n a h i g h e r o v e r a l l c o n v e r s i o n o f f e r r o - t o f e r r i c y a n i d e ,
T h e o n l y r e q u i r e m e n t s of t h e c a t h o d e s o l u t i o n a r e : t h a t i t b e c o n d u c t i v e , and t h a t i t n o t c o n t r i b u t e o t h e r r e a c t i o n s a t t h e c a t h o d e t h a t would d e c r e a s e t h e c e l l e f f i c i e n c y .
Ozone Conver s ion o f F e r r o - t o F e r r i c y a n i d e
The s t o i c h i o m e t r i c r e l a t i o n s h i p f o r t h e o x i d a t i o n o f f e r r o - c y a n i d e t o f e r r i c y a n i d e w i t h ozone i s a s f o l l o w s :
2 Na4 Fe(CN)6 1 0 H 2 0 + 0 3 + H 2 0 -+ 2 Nag Fe(CN)6 + 02 + 2 NaOH +
20 H 2 0 (7 )
T h i s r e a c t i o n shows t h a t 2 0 . 2 gm o f sodium f e r r o c y a n i d e c a n b e c o n v e r t e d t o 1 1 . 7 gm of sodium f e r r i c y a n i d e by one gram o f ozone . ('14)
With an o x i d a n t a s r e a c t i v e as ozone , t h e r a t e d e t e r m i n i n g s t e p i n t h e above r e a c t i o n s h o u l d b e t h e mass t r a n s f e r o f ozone from t h e gaseous t o t h e s o l u t i o n p h a s e .
I f t h e r a t e o f r e a c t i o n be tween ozone and f e r r o c y a n i d e i s v e r y r a p i d , t h e s o l u t i o n c o n c e n t r a t i o n o f ozone w i l l be n e a r z e r o . Thus , :ne r a t e of a b s o r p t i o n i s p r o p o r t i o n a l t o t h e p a r t i a l p r e s s u r e o f ozone . ( 1 5 )
Ozone Decomposi t ion o f F e r r o c y a n i d e
The d e c o m p o s i t i o n o f t h e f e r r o c y a n i d e i o n h a s b e e n found t o b e a v e r y complex mechanism, i n v o l v i n g a number of compet ing r e a c t i o n s . j l 6 )
(1 p w
- 3 + 2 OH- + 0 2 (8) 2 Fe(CN)6 - 4 + O 3 + H 2 0 + 2 Fe(CNj6
Fe(C,U)be3 Z Fe+3 + 6 CN-
D e s t r u c t i o n o f f r e e c y a n i d e i o n
( 9 )
C N - + O j + OCN- + 02 ( 1 0 )
D e s t r u c t i o n o f c y a n a t e i o n
OCN- + 2H+ + H 2 0 + C02 + NHq'
O C N - + NH4+ + * NH2 CONH2
2 OCN- + H 2 0 + 303 -+ 2 H C O - 3 + N 2 + 3 02
(11)
( 1 2 )
( 1 3 )
12
Fe 1
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0x8
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In
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F e r r o c y a n i d e h y d r o l y s i s
Free c y a n i d e b r e a k s down r e a d i l y i n t h e p r e s e n s e o f ozone t o t h e c y a n a t e i o n , which i s g e n e r a l l y c o n s i d e r e d t o be o n l y one o n e - t h o u s a n d t h ( 1 / 1 , 0 0 0 ) a s t o x i c a s c y a n i d e . The c y a n a t e i o n is n o t s t a b l e unde r o x i d a t i o n c o n d i t i o n s , b u t i t s o x i d a t i o n r e a c t i o n i s n o t w e l l u n d e r s t o o d . A p p a r e n t l y , t h e breakdown con- s i s t s o f a combina t ion of r e a c t i o n s , i n c l u d i n g b o t h h y d r o l y s i s and o x i d a t i o n .
The r e a c t i o n o f f e r r i c y a n i d e and ozone a p p a r e n t l y i n v o l v e s t h e removal o f a cyano g roup from t h e f e r r i c y a n i d e complex. Th i s complex t h e n f u r t h e r decomposes t o c y a n a t e and f e r r i c i o n s .
I n t h e p r e s e n c e o f m i n e r a l a c i d s , i r o n c y a n i d e complex i o n s de - compose v i a t h e f o l l o w i n g r e a c t i o n :
3 Hq Fe(CN)6 * 1 2 H C N + F e 2 Fe(CN)6 (1 5)
The f e r r o u s f e r r o c y a n i d e c a n , i n t u r n , be o x i d i z e d t o P r u s s i a n Blue F e 4 [Fe(CN)6] . The e x t e n t o f t h i s d e c o m p o s i t i o n depends upon t h e a c i d i t y 02 t h e s o l u t i o n ; i n c r e a s i n g as t h e pH d e c r e a s e s .
F e r r o c y a n i d e r e a c t s d i f f e r e n t l y i n t h e p r e s e n c e o f o x i d i z i n g a g d s . A t t e m p e r a t u r e s be tween 7 0 " and 80°C, h y p o c h l o r o u s a c i d c o n v e r t s f e r r o c y a n i d e t o f e r r i c y a n i d e , n i t r o p r u s s i d e and f r e e f e r r i c i o n s . When n i t r i c a c i d i s added t o an aqueous f e r r o - c y a n i d e , t h e r e a c t i o n p r o d u c t s a r e r e p o r t e d as f e r r i c y a n i d e , n i t r o p r u s s i d e , hydrogen c y a n i d e , cyanogen , c a r b o n d i o x i d e , oxamide and n i t r o u s a c i d . (16)
Removal o f Heavy Meta l Complex Cyan ides
Heavy m e t a l f e r r o c y a n i d e s a r e o n l y s l i g h t l y s o l u b l e i n water . S o l u b l e s a l t s of t h e heavy m e t a l i o n s a r e u s e d t o form heavy metal f e r r o c y a n i d e s i n t h e f o l l o w i n g manner:
MX + H 2 0 + M -
(16) ++ + X- + H20 (Meta l I o n i z a t i o n )
-+ M2 Fe(CN)6+ (Heavy Metal P r e c i p i t a t i o n ) ( 1 7 ) M++ + Fe(CN)6 -4
I n t h e p r e s e n c e o f an e x t e r n a l f i e l d , t h r e e f o r c e s a c t on a p a r t i c l e which i s moving th rough a l i q u i d . These f o r c e s a r e : . (1) t h e e x t e r n a l f o r c e ( g r a v i t a t i o n a l o r c e n t r i f u g a l ) ; ( 2 ) t h e bouyan t f o r c e ; and (3) t h e d r a g f o r c e . By t h e a p p l i c a t i o n o f S t o k e s law f o r s p h e r i c a l p a r t i c l e s , t.he r a t e o f s e t t l i n g i s d i r e c t l y p r o p o r t i o n a l t o t h e s q u a r e o f t h e r a d i u s o f t h e p a r - t i c l e and t h e d e n s i t y o f t h e p a r t i c l e , and i n v e r s e l y p r o p o r -
t i o i i n l t o t h e v i s c o s i t y of t h c f l u i d . T h e r c f o r e , t h e a d d i t i o n o f a c o a g u l a t i o n a g e n t w i l l i n c r e a s e t h e r a t e of s c t t l i n g o f - t h e p r e c i p i t a t e s due . t o an i n c r e a s e i n p a r t i c l e s i z e ,
C h l o r i n e D e s t r u c t i o n o f Complcx Cyan ides - Var ious r e a c t i o n s have b e e n s u g g e s t e d o r obse rved f o r c h l o r i n e o x i d a t i o n of complex c y a n i d e s . p u r e g a s , a s a s o l u t i o n , o r i n s o l i d form.
h y p d c h l o r i t e i o n as f o l l o w s : ( i 8 j
C h l o r i n e may be added a s a
Gaseous c h ~ o r h n o reacts in &A alkaline solut ion t o form the
C12 + OH- + OC1- + C1- + H+
Fe(CN)6-4 Fe++ + 6 CN- (19)
( 1 8 )
S e v e r a l p o s s i b l e compet ing r e a c t i o n s f o r t h e d e s t r u c t i o n o f f e r r o c y a n i d e by c h l o r i n e a r e c i t e d i n t h e l i t e r a t u r e ; t h e y a r e a s f o l l o w s :
CN-' + OC1- * OCN- + C1- (20) - 2 OCN + 3 OC1- + H20 -+ 2 C02 + N 2 + 2 C1- + OH- (21).
OCN- + 2H+ + H20 + C 0 2 + NH4 +
OCN- + NH4 + N H ? I CONH, .d (23)
OCN- + OH- + 11-9 .- -+ c3- s + NH3 (24)
(22) +
- -
As i n a ~ o i ; ~ : ~ a i i , :.'.c ~ : s t r a c t i o n o f t h e f r c e c y a n i d e i o n i s a r a p i d and w e i l known 2 r o c e s s , w h i l e t h e d e s t r u c t i o n o f t h e cyan- a t e i s s l o w e r and more complex.
The p redominan t s p e c i e s i n s o l u t i o n , w h e n c h l o r i n e i s b u b b l e d i n t o w a t e r o v e r t h e pH r a n g e o f 2 - 6 , i s hypoch lo rous a c i d (HOC1). As ment ioned p r e v i o u s l y , h y p a c h l o r o u s a c i d c o n v e r t s f e r r o c y a n i d e t o f e r r i c y a n i d e , n i t r o p r u s s i d e and f r e e f e r r i c i o n s .
Rate dependence on c a t a l y s t c o n c e n t r a t i o n i s c h a r a c t e r i s t i c o f homogeneous c a t a l y s i s . The c a t a l y s t u s u a l l y a c t s by p r o v i d i n g a mechanism f o r t h e d e c o m p o s i t i o n t h a t h a s c o n s i d e r a b l y ' l o w e r a c t i v a t i o n e n e r g y t h a n t h e u n c a t a l y z e d r e a c t i o n .
Lancy r e p o r t e d t h a t m e r c u r i c s a l t s s p l i t t h e i r o n c y a n i d e s i n a c a t a l y t i c p r o c e s s a l k a l i n e c h l o r i n a t i o n , The p r o p o s e d d e c o m p o s i t i o n i s as f o l l o w s :
(19)
i f t h e d e c o m p o s i t i o n i s coup led w i t h a n
.
14
Hg
2 N
In f c 1' t h e cy a cl; 1 f e r hy:. on 2 o r
DUE s t L P =c
i t i o n o f
I r i n e 1
f
:d
inide roc1)-.
: o f l i ng f e r '
i n .n
1x1 t h i s w o r k , oll ly one mole o f c y a n i d e i s c h l o r i n a t e d f r o m t h e f e r r i c y a n i d e coniples. t h e s e c o n d a r y breakdown o f t h e c y a n i d e compounds w i l l b e t o c y a n a t e s a l t s . The p r o c e d u r e u s e d by Lancy was t o f i r s t hypo- c h l o r i n a t e t h e w a s t e t o c o n v e r t t h e simple c y a n i d e s and o x i d i z e f e r r o - t o f e r r i c y a n i d e . h y p o c h l o r i n a t i o n c o n t i n u e d . one gram p e r l i t e r o f f e r r i c y a n i d e i n t w e n t y - f o u r h o u r s a t 70°F o r i n two h o u r s a t 1 8 0 ' F . ( 2 0 ) ( 2 1 )
The pII must b e a l k a l i n e t o i n s u r e t h a t
The HgC12 c a t a l y s t i s t h e n added and T h i s method was found t o d e s t r o y
Due t o t h e p o l l u t i o n h a z a r d s i n t h e u s e o f m e r c u r y , i t was n o t s t u d i e d i n t h i s r e p o r t . R a t h e r , o t h e r c a t a l y s t s t h a t migh t produce a s imi la r o x i d a t i o n were i n v e s t i g a t e d .
MATE 1: I A L S
NATE li I A L S
Chemical
P o t a s s i u m F e r r o c y a n i d e
P o t a s s i u m F e r r i c y a n i d e
H y d r o c h l o r i c Acid
Sodium Hydroxide
F e r r o u s S u l f a t e
lcanganous S u l f a t e
C u p r i c S u l f a t e
Cadmium S u l f a t e
Z inc C h l o r i d e
N a l c o l y t e , 6 7 0
P u r i f l o c A - 2 3
S t e e l Wool
AND APPAIUTUS
Grade
c r y s t a l
c r y s t a l
3 7 . 8 %
p e l l e t s
g r a n u l a r
p u r i f i e d
t e c h n i c a l
c r y s t a l
t e c h n i c a l
n o n i o n i c f l o c c u l a n t
a n i o n i c f l o c c u l a n t
Grade 3
3ource
J . T . Baker
J . T . Baker
J. T. Baker
J . T . Baker
J . T . Baker
J . T . Baker
W i l l S c i e n t i f i c
J . T . Baker
J . T . Baker
Nalco Chemical Co.
Alken Murray Corp.
Unknown
1 7
. . . . . . . . . , . . . . . . . . . . . . . . . . . .
S p e c t r o p h o t o m e t e r : P e r k i n - E l m e r . Model 139
pH N e t e r : C o r n i n g Model 1 2 R e s e a r c h
B a l a n c e : N e t t l e r H - 1 0 M a c r o a n a l y t i c a l Balance ; c a p a c i t y : 1 6 0 ~ 0 . 0 0 0 0 5 gms
B u r e t t e s : 5 0 . 0 ml
P i p e t s : 1 m l , 5 m l , 1 0 m l , 2 0 ml.
E l e c t r o lys i s o f F e r r o c y a n i d e s
V a r i a c : P o w e r s t a t V a r i a b l e A u t o t r a n s f o r m e r t y p e 1 1 6 B , t h e S u p e r i o r E l e c t r i c Co. , 0 - 1 4 0 VAC
R e c e i f i e r : Varo , t y p e 1 N 4437
Ammeter: Wes te rn Model 8 0 A n a l y z e r , 0.100 amperes
V o l t m e t e r : T r i p l e t t , Model 310 M i n i a t u r e VOM
S t i r r e r : L a b - S t i r , h o l l o w s p i n d l e , Ebe rbach Corp .
Non -Nemb r a n e C e l l
Anodes: S t a i n l e s s S t e e l S c r e e n C y l i n d e r s , Anrod S c r e e n C y l i n d e r C o . , Cass C i t y , M i c h i g a n ; l", 1 . 5 " , 2 . 2 5 " , 3,.25" d i a m e t e r
Ca thodes : S t a i n l e s s S t e e l Rods, U.S.S., 1 / 8 , 1 / 4 , 1 / 2 i n c h d i a m e t e r
Membrane C e l l
R e a c t o r : (See F i g u r e 1, Page 2 2 ) c o n s i s t s o f two p l e x i g l a s s compar tmen t s e a c h 2"W x 3 1 / 2 "L x 4 1 / 2 " H
E l e c t r o d e s : Carbon p l a t e s 3" H x 3" L x 1/4"W ( E l e c t r o Carb EC-4)
S e a l a n t : Dow C o r n i n g , RTV Cement
Membranes: I o n i c s I n c . , C a t i o n No. G1-AZL-066, Watertown M a s s a c h u s e t t s
P i l o t P 1 a n t C e l l
R e a c t o r : (See F i g u r e 3 page 2 6 ) C o n s i s t s o f t h r e e c y l i n d r i c a l p l e x i g l a s s columns w i t h anodes on i n s i d e w a l l s and c a t h - o d e s on c e n t r a l a x e s 36"H x 3"I .D. x 1/ .4"Wall T h i c k n e s s
18
AnoJie
catho
Power
Pump :
F 1 OW
Ozone
A l l S
A i r P
-
Ozone
Bench
React
-
P i l o t
React
Pump :
F l o w
- Bend
Hot I:
Reacl
Spar$
I
AnoJes : Stainless S t c c l P c r i ' o r a t c d C y l i n d c r s , 36" x 3 " O . D.
Cathodes: S t a i n l e s s S t c c l R o d l / S l ' d i a m e t c r , U . S . S .
power S u p p l y : iiollaJ:d Rcctificr, J . H o l l a n d and S o n s , 0-iOV U . C . , 2 5 amperes .
pump:
Flow F ie t e r : F . i d . Dwyer M f g . Co. t y p e VFA-34-BV r a n g e ; 2 0 - 2 0 0
Narch b l a n u f a c t u r i n g C o . , Model L C - 2 A , 115V A . C . , 6 0 c y c l e . Glenview, I l l i n o i s .
ml/min, Michigan C i t y , I n d i a n a ,
Ozone R e g e n e r a t i o n and D e s t r u c t i o n of Complex Cyan ides
. A l l s t u d i e s u s e d t h e f o l l o w i n g equ ipmen t :
A i r P r e p a r a t i o n Sys tem: P u r i f i c a t i o n S c i e n c e s I n c o r p o r a t e d , Geneva, New York, Model AP-1; De\ ipoin t : -40°C; C a p a c i t y : 1 . 8 SCFM a t 8 0 ?SIG.
Ozone G e n e r a t o r : P u r i f i c a t i o n S c i e n c e s I n c o r p o r a t e d , Geneva, New York, Model LOA-2; Flow: 0 - 2 0 SCFH; O u t p u t : 0 - 3 grams p e r hour w i t h p u r e oxygen f e e d .
Bench Top R e g e n e r a t i o n
R e a c t o r : Hydrometer Column; 1 8 1/.2"H x 2 1 / 2 " O . D . x 1 / 8 " i i a l l T h i c k n e s s .
Labpor Gas D i s p e r s i o n Tubes ; B e l - A r t P r o d u c t s , P e q u a n n o c k , N e w J e r s e y ; p o l y e t h y l e n e c a n d l e s , medium p o r o s i t y .
S p a r g e r :
P i l o t P l a n t R e g e n e r a t i o n - (See F i g u r e 4, p a g e 2 7 )
R e a c t o r : C l e a r P l e x i g l a s s Column; 52"H x 3 1 / 2 " I , D . x 1/4" Wall T h i c k n e s s
Pump: March M a n u f a c t u r i n g Co. ; Model L C - 2 A , 1 1 5 v o l t s , 60 c y c l e .
Flow Meter: F.W. Dwyer M a n u f a c t u r i n g Co. ; t y p e VFA-34-BV, r a n g e 20-200 ml/min.
Bench Top D e s t r u c t i o n
Hot P l a t e : Dy la the rm, Model 25202, 5 0 0 w a t t s
R e a c t o r : Kimax B e a k e r , 1 0 0 0 m l .
S p a r g e r : Labpor Gas D i s p e r s i o n Tube; B e l - A r t P r o d u c t s , Pequannock, New J e r s e y ; P o l y e t h y l e n e c a n d l e s , medium p o r o s i t y .
19
Prccipitation
Agitator: Phipps and Bird Six Bladc Multiple Stirrer, O - t l O O rpiii, 1 1 5 v , GO cycle, with florescent 1 amp base i 1 1 uin i n a t o r
Puiiip:
Heater: Sethco Immersion Heater
Eberbach Circulating Pump, Model AA2G108
Centrifugation (See Figure 9, page 3 5 )
Flowmeter: F. W. Dwyer Mfg. Co., Model VFA-34-bv, range 20-200 ml/min
Centrifuge: Sorvall Superspeed Centrifuge with Szent-Gyorgi Blum Continuous Flow Apparatus; Model SS-1, Ivan Sorva\ll Corp., Norwalk, Conn.
. Chlorine Destruction of Complex Cyanides
Chlorine: Bottled, Jones Chemical Co., Caledonia, New York
A s e i me as t The r titri
The 2
were
In ac of SI ultrz test detez
Hypochlorite Solution: Clorox Bleach, Std. 5% hypochlorite The s concentration Apper
Gas Dispersion Tubes: Labpor Polyethylene Candles, Bel-Art Products, Pequannock, New Jersey, medil porosity
Will Gyrathern Stirrer-Hot Plate, Magnetic 60-80 rpm, 0-700°F, Model IIa
Heater:
2 0
~p base
ange
t -Gyorg i S - 1 , Ivan
ew York
h l o r i t e
P R O C E D U R E S
A n a l y t i c a l (Subprogram A)
A sca rc1~ o f the literature yiolded a numbcr o f methods f o r n ~ e a s u ~ i n g t h e c o n c e n t r a t i o n s o f f e r r o c y a n i d e and f e r r i c y a n i d e , The methods i n c l u d e d : c e r i m e t r i c , i o d o m e t r i c and p o t e n t i o m e t r i c t i t r a t i o n s and one c o l o r m e t r i c measurement ,
The above methods were t e s t e d i n t h e l a b and v a r i o u s m o d i f i c a t i were made t o improve t h e a c c u r a c y o f t h e measu remen t s .
I n a d d i t i o n t o t h e methods found i n t h e l i t e r a t u r e , a number of s p e c t r o p h o t o m e t r i c p r o c e d u r e s were d e v e l o p e d u s i n g b o r h t h e u l t r a - v i o l e t and v i s i b l e l i g h t r e g i o n s . The s p e c t r o p h o t o m e t r i c t e s t p r o c e d u r e s were compared w i t h t h e t i t r a t i o n p r o c e d u r e s t o d e t e r m i n e which gave t h e b e s t a c c u r a c y i n t h e s h o r t e s t t i m e ,
The s e l e c t e d p r o c e d u r e s u s e d i n t h i s p r o j e c t c a n b e found i n Appendix D n Page 123,
21
O A S
f
i
I i
E l c c t r o l y s i s o f F c r r o c y a n i d c s (Subprogram U)
sa11 - ;\lCllIb r n l l c c c 11
Thc p o t a s s i u m f e r r o c y a n i d e , IidFe(CN) 6 . 3H20 s o l u t i o n s wcrc p r c - pa red by f i r s t d i s s o l v i n g 10.00+.01 grams o f t h c c r y s t a l i n d i s t i l l e d w a t e r and t l i cn b r i n g i n g t h e t o t a l volume t o one l i t e r , T h i s p roduced a 5 . 0 3 g r a m / l i t e r s o l u t i o n o f i r o n complex c y a n i d e a s Fe(CN)6. F i v e hundred m i l l i l i t e r s o f t h i s s o l u t i o n were added t o a one l i t e r b e a k e r i n which t h e e l e c t r o d e s were immerse( t h u s fo rming t h e c e l l . The power s u p p l y was c o n n e c t e d and t h e v o l t a g e a d j u s t e d t o 3 .5 v o l t s D . C . The r a t i o of c u r r e n k d e n s i t y on t h e c a t h o d e t o c u r r e n t d e n s i t y on t h e anode v a r i e d be tween 0 . 1 and 2 0 . 3 by u s i n g d i f f e r e n t s i z e anodes and c a t h o d e s . Sam- p l e s were c o l l e c t e d v i a a p i p e t f o r a n a l y s i s a t v a r i o u s t i n e s f o r e a c h c u r r e n t d e n s i t y r a t i o .
Tempera tu re s t u d i e s were conduc ted m e a s u r i n g t h e i n c r e a s e i n c u r r e n t ove r a s p e c i f i c t e m p e r a t u r e r a n g e on a number o f c e l l s w i t h c u r r e n t d e n s i t y r a t i o s between 1 and 1 6 . The c e l l s were p l a c e d on a h o t p l a t e and a l l o w e d t o come t o e q u i l b r i u m a t t h e t e m p e r a t u r e u n d e r c o n s i d e r a t i o n and t h e c u r r e n t was t h e n measur - e d . E l e c t r o d e d e p t h , a p p l i e d v o l t a g e , and c o n c e n t r a t i o n were h e l d c o n s t a n t f o r e a c h c e l l . Tempera tu res were v a r i e d f rom 25OC t o 6OoC i n f i v e d e g r e e i n t e r v a l s .
Rec t Bri
Jlembrane Cell
A c a t i o n i c membrane s e p a r a t e s two i n d i v i d u a l c e l l compar tments i n t h e membrane e l e c t r o l y s i s c e l l : t h e anode (+) and t h e c a t h - ode ( - ) . O x i d a t i o n r e a c t i o n s o c c u r a t t h e anode , t h e s o l u t i o n b e i n g r e f e r r e d t o as t h e a n o l y t e . The c a t h o l y t e s o l u t i o n con- t a c t s t h e c a t h o d e .
For t e s t s a t ambien t t e m p e r a t u r e , t h e a n o l y t e compartment was f i l l e d w i r h 350 m l o f 0 . 0 1 M p o t a s s i u m f e r r o c y a n i d e , K4Fe(CN)6-3H20. The c a t h o d e compartment was f i l l e d w i t h d i s - t i l l e d w a t e r , t o which a c i d (HC1) was added t o i n c r e a s e conduc- t i v i t y . The v o l t a g e was s e t a t 3 . 5 v o l t s D . C . and t h e c u r r e n t c o n t i n o u s l y m o n i t o r e d .
F u r t h e r s t u d i e s were made a t v a r y i n g t e m p e r a t u r e s by immers ing t h e c e l l i n a c o n s t a n t t e m p e r a t u r e w a t e r b a t h . T e m p e r a t u r e s '
r a n g e d from 25OC t o 50°C i n f i v e d e g r e e i n t e r v a l s . Amperage measurements were made a t v a r i o u s t e m p e r a t u r e l e v e l s .
Figu
22
!re prc- .1 in !ne liter x cyanid were e immersl and the densit;
etween s. Sam- times
se in f cells
at the I measur- 1 were :rom
j Were
'tments .e cath- Nlution n con-
t was
dis- onduc- urrent
ersing Jres rage
Recti Brid
Stirrer
Voltmeter
fier ge P, I Ammeter
Screen Anode
Variac
Figure 1 Bench Top Non-Membrane Electrolysis Cell
P i ! c 7 i I ’ l n i i t I ; c . ~ c i ~ c ~ r n t i o i i Ccll
T h e i c l l was dcs ig i i cd t o r u n a s a c o n t i n u o u s €low s y s t c m . A 10.00+.01 g r a i i i / l i t c r p o t a s s i u m f e r r o c y a n i d e ( K 4 F c ( C N ) 0 3 1 1 ~ 0 ) s o l u t i o n was p r e p a r c d aiici p l a c e d i n a h o l d i n g t a n k . t i o i i \\*as i nc t c rcd i n t o t h e c c l l a t v a r i o u s f l o w r a t e s f rom 1 5 0 ml/min t o 500 ml/inin t l i rougl i a f l o w m c t c r . The c e l l voltage 1i3s a d j u s t e d t o 3 . 5 v o l t s U . C . Ovc r i low samples were t a k e n p e r i o d i c a l l y a n d a n a l y z e d f o r f e r r i c y a n i d e . The c u r r e n t was m o n i t o r e d c o n t i n u o u s l y a n d t h e c e l l e f f i c i e n c y compared t o t h e t h e o r e t i c a l e f f i c i e n c y as computed from Faraday’ s Law.
.fi h i s s o l u .
24
t cm. A I * 3f120) t h i s s o l u from 1 5 0 ) I t a g e t a k e n
: n t was :d t o the
kiemb r a n e
Figure 2 Membrane Electrolysis Cell
1 Plexiglass Electrolyte Compartment
25
. .
u Kegenerated Ferricyanide
'l- 0 Cat ha de Powcr
I i 2 Exh
bQ
JJ
Drain -
aus t
- To Anode Power
Flowmeter i - e- Ferrocyanide
Figure 3 Pilot Plant Non-Membrane Electrolysis Cell
Power
?r
- so cyanid)
2 7
.--
Figure 4 Pilot P l a n t Electrolytic Cell
Ozone R e g e n e r a t i o n and D e s t r u c t i o n o f Complex Cyan ides
(Subprogram C)
Bench Top R c g e n e r a t i o n
One l i t e r o f a 1 O k . 0 1 g r a m / l i t e r p o t a s s i u m f e r r o c y a n i d e {S4Fe(CN)6-3H 01, was p l a c e d i n t h e r e a c t i o n column and t h c f l o w o f t h e ozone i a s s t r e a m i n t o t h e r e a c t o r a d j u s t e d t o 5 SCI;H. Saniplcs were t a k e n a t v a r i o u s t imes d u r i n g t h e o x i d a t i o n and a n a l y z e d f o r pH and f e r r i c y a n i d e . d e t e c t e d ( s m e l l e d ) above t h e s o l u t i o n s u r f a c e , t h e system was sliu t down.
A t t h e p o i n t ozone c o u l d b e
C o n s t a n t pH s t u d i e s were a l s o pe r fo rmed u s i n g t h e above method w i t h t h e a d d i t i o n o f pH m o n i t o r i n g and c o n t r o l ; c o n c e n t r a t e d h y d r o c h l o r i c a c i d was added d ropwise t o t h e column t o m a i n t a i n a c o n s t a n t pH. were r e c o r d e d w i t h e a c h sample . S o l u t i o n s were a n a l y z e d f o r f e r r o c y a n i d e and f e r r i c y a n i d e ; and ma te r i a l b a l a n c e s c a l c u l a t e d .
The volume o f a c i d u s e d and t h e time o f r e a c t i o n
P i l o t P l a n t R e g e n e r a t i o n
For t h e p i l o t p l a n t s t u d i e s , 50 g a l l o n s o f 30 g r a m / l i t e r po- t a s s i u m f e r r o c y a n i d e {K4Fe(CN)6 '3H20~ s o l u t i o n were p r e p a r e d and p l a c e d i n a h o l d i n g t a n k . The s o l u t i o n was pumped i n t o t h e r e a c t i o n column t h r o u g h a f l o w meter a t f low r a t e s f rom 5 0 - 1 5 0 ml/min. The ozone gas s t r e a m , c o n t a i n i n g a 2 % (by v o l - ume) ozone c o n c e n t r a t i o n , was i n t r o d u c e d i n t o t h e v e s s e l a t 5 SCFH t h r o u g h a s p a r g e r t u b e a t t h e bo t tom.
Samples were t a k e n a t s e l e c t e d time i n t e r v a l s and a n a l y z e d f o r f e r r o c y a n i d e , f e r r i c y a n i d e , and pH.
Bench TOD D e s t r u c t i o n
S t o r 4 Tank : Fred
Solut:
A 0 . 0 1 Iy s o l u t i o n o f p o t a s s i u m f e r r o c y a n i d e .{K4,Fe(CN)6*3H20) was p r e p a r e d and 5 0 0 m l p l a c e d i n a one l i t e r b e a k e r . a d j u s t e d w i t h H C 1 o r N a O H a s r e q u i r e d . Ozont
The pHwas
T h r e e r e a c t i o n schemes were i n v e s t i g a t e d . F i r s t , ozone was b u b b l e d i n t o t h e sample w i t h o u t pH a d j u s t m e n t o r t e m p e r a t u r e c o n t r o l . f e r r i c y a n i d e . r e a c t i o n . Second , ozone was b u b b l e d i n t o a h i g h l y a c i d i s i e d s o l u t i o n , u s i n g a s t e e l wool c a t a l y s t . The p r o c e d u r e was a s a b o v e , w i t h t h e a d d i t i o n o f 5 grams o f s t e e l wool and 2 0 m l o f H C 1 t o t h e s o l u t i o n b e f o r e ozone was i n t r o d u c e d . T h i r d , t h e s o l u t i o n was a c i d i f i e d w i t h 20 m l H C 1 and h e a t e d . When t h e d e s i r e d t e m p e r a t u r e was r e a c h e d , ozone was i n t r o d u c e d i n t o t h e s o l u t i o n . Samples were t a k e n p e r i o d i c a l l y and a n a l y z e d f o r f e r r i c y a n i d e .
Samples were t a k e n p e r i o d i c a l l y and a n a l y z e d f o r Tempera tu re and pH were r e c o r d e d t h r o u g h o u t t h e
The t e m p e r a t u r e s s t u d i e d r a n g e d from 70'C t o 90°C.
E
2 8
. h e flow lcI:iI. , and 'uld be m was
method ated intain reaction for
ulated.
P O - ared nto rom y vol- at
zd for
ras :ure )r it the 'ied as 11 of the he o the O O C .
mide
T I
F 1 ow Meter
- I i
Storage Tank for Fresh
Solution
n
7 k
- E x h a u s t G a s e s t o hood
f Sump Pump ,
Plexiglass Column
Ozone from Generator - li
Figure 5 Pilot Plant Ozone Regeneration Cell
4 I Storage Tank for
Regenerated Solution
I
Figure 6 Laboratory Ozone Generator and Air Preparation Systel
30
F i g L r a 7 Pilot Plant Ozonation o r Chlorination CelL
31
Removal o f Heavy Meta l Complex Cyan ides
(Subprogram D )
P r e c i p i t a t i o n
F e r r o - a n d f e r r i c y a n i d e p r e c i p i t a t e s were formed from a s o l u t i o n c o n t a i n i n g 750 mg/l of t o t a l complex iron c y a n i d e a s F e ( C N ) 6 . Pr imary t e s t i n g was conduc ted a t 2 O 0 C + 1 " C . Secondary t e s t s were made a t 1 6 ' C , 2 6 O C and 4 6 ' C . The i n i t i a l pH o f a l l s o l u - t i o n s was a d j u s t e d t o 8 . 0 k . 1 . For t h e pH s t u d i e s , , i n i t i a l v a l u e s o f 2 . 0 , 6 . 0 , 8 . 0 , and 1 1 . 0 were i n v e s t i g a t e d . E i t h e r hydro - c h l o r i c a c i d o r 2 . 5 N sodium h y d r o x i d e was u s e d t o a d j u s t t h e PH*
7 5 0 ml of s t o c k complex c y a n i d e s o l u t i o n was p l a c e d i n g o n e l i t e r b e a k e r and t h e pH a d j u s t e d as r e q u i r e d . was t h e n p l a c e d on t h e m u l t i p l e s t i r r e r and s t i r r e d a t 100 rpm. Using an u p r i g h t g r a d u a t e d p i p e t , t h e r e q u i r e d amount of heavy m e t a l s a l t s o l u t i o n was added t o form t h e p r e c i p i t a t e . The m i x t u r e was a l l o w e d t o s t i r f o r f i v e m i n u t e s , , a t which p o i n t t h e s t i r r i n g p a d d l e s were removed.
A d e f i n i t e l i n e o f s e p a r a t i o n e x i s t e d be tween t h e s u p e r n a t a n t and t h e c l o u d y l a y e r . A t time i n t e r v a l s of 5 , 1 0 , 20 and 30 m i n u t e s , t h e h e i g h t o f t h i s l i n e was measured from t h e botcom o f t h e r e a c t i o n v e s s e l and u s e d t o c a l c u l a t e s e t t l i n g r a t e s .
The s o l u t i o n
Twenty m i l l i l i t e r s amples were c o l l e c t e d a t a p o i n t one q u a r t e r i n c h below t h e s o l u t i o n s u r f a c e a t e a c h r e c o r d i n g o f s e t t l i n g t ime .
C e n t r i f u g a t i o n ( F o r e x a c t t e s t p r o c e d u r e see Appendix C)
The c e n t r i f u g a t i o n t e s t s were c o n d u c t e d u s i n g two f l o c c u l a n t s , N a l c o l y t e 6 7 0 and P u r i f l o c A - 2 3 , o v e r t h e c o n c e n t r a t i o n r a n g e o f 0 . 0 t o 1 0 . 0 mg/l by w e i g h t o f f i v e heavy metal i o n s ( F e + 2 , Mn+2, Cu ', Zn+y and Cd c o n d i t i o n s o f :
Tests we$ cond c t e d on+sach ) u n d e r
C o n s t a n t f l o w r a t e t h r o u g h t h e s y s t e m and v a r i a b l e c e n - t r i f u g e r o t o r s p e e d w i t h v a r i o u s f l o c c u l a n t c o n c e n t r a t i o n s .
C o n s t a n t r o t o r s p e e d and v a r i a b l e f l o w r a t e w i t h v a r i o u s f l o c c u l a n t c o n c e n t r a t i o n s .
One g a l l o n o f a 1 . 5 0 + 0 . 0 1 g r a m / l i t e r s o l u t i o n o f p o t a s s f u m f e r r o c y a n i d e [KqFe(CN)6'3H20] was p l a c e d i n a c a r b o y on a s t a n d above t h e l e v e l o f t h e c e n t r i f u g e ( F i g u r e 9 , page 3 5 ) . The pH o f t h e s o l u t i o n was a d j u s t e d t o 6 . 4 2 0 . 2 and t h e t e m p e r a t u r e 20°C+10C.
32
.ution U
G*
:S
,olu
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the
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-
ne n e avy e t rpm
.
an
t 30 tom
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.
arte
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IUS
i tand
f
pH !
35
i
A s t i r r e r was a r r a n g e d s u c h t h a t t h e b l a d e was be tween 2 and 3 i n c h e s above t h e bot tom of t h e c a r b o y , o p e r a t e d a t 100 rpm. A 10: e x c e s s o f heavy m e t a l s a l t s o l u t i o n , o v e r t h e s t o i c h i o - met r ic r e q u i r e m e n t , was added t o t h e ca rboy and t h e r e s u l t i n g s l u r r y agi:atcd Tor an a d d i t i o n a l f i v e m i n u t e s .
The c e n t r i f u g e was s t a r t e d and b r o u g h t t o 6500 rpm. f low of s l u r r y was i n i t i a t e d and t h e c o l l e c t i o n t u b e s f i l l e d . Flow was d i s c 0 n t i n u e . d and t h e c o n t e n t s o f t h e t u b e s a l l o w e d t o s t a b i l i z e f o r f i v e m i n u t e s a t 6500 rpm.
The " r o t o r s t u d y " was conduc ted by i n c r e a s i n g r o t o r s p e e d s t e p . wise from 6500 rpm t o 15 ,800 rpm and t h e n back t o 6 5 0 0 rpm. Flow th rough t h e c e n t r i f u g e d u r i n g t h i s s t u d y was c o n s t a n t .
The " f low s t u d y " was conduc ted by i n c r e a s i n g t h e s l u r r y f low r a t e t h rough t h e s y s t e m s t e p w i s e f rom 6 ml/min t o 2 0 0 ml/min and t h e n d e c r e a s i n g a g a i n t o 6 ml/min. t h i s s t u d y was c o n s t a n t .
For each o f t h e f i v e m e t a l i o n s , a f l o w s t u d y and a r o t o r study was conduc ted a t each o f t h e v a r i o u s f l o c c u l a n t c o n c e n t r a t i o n s , Samples were t a k e n a t each i n c r e m e n t o f f l o w r a t e o r r o t o r s p e e d .
Absorbance o f t h e samples was measured a t 2 2 0 m u ; an absorbance peak f o r f e r r o c y a n i d e . pended m a t e r i a l .
The g r a v i t )
The r o t o r s p e e d d u r i n g
.
T h i s measures b o t h d i s s o l v e d and s u s -
x k k ' 3 dl r/)
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en 2
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us
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35
C h l o r i n e D e s t r u c t i o n 'of Complex Cyanides
(Subprogram E )
Two a p p r o a c h e s t o c h l o r i n a t i o n ( o r h y p o c h l o r i n a t i o n ) were e v a l u a t e d : a h y p o c h l o r i t e s o l u t i o n and c h l o r i n e g a s .
For t h e f i r s t s e r i e s of e x p e r i m e n t s , 5 0 0 ml were added t o 5 0 0 ml o f 10.0+0.1 g r a m / l i t e r ' g a n i d e [K3Fe(CN)b] s o l u t i o n , The pH was ad Measurements were made o v e r t h e t e m p e r a t u r e m0O"C. Samples were t a k e n a t v a r i o u s t i m e s f e r r i c y a n i d e .
of Clorox b l e p o t a s s i u m f e r . j u s t e d t o 11. r a n g e o f 20°C
and a n a l y z e d
a c h r i - 0 + 1 . -
t o f o r
0.
For t h e sccor ld s e r i e s , c h l o r i n e g a s was bubb led i n t o one l i t e r of a 10.01tO.1 g r a m / l i t e r s o l u t i o n o f p o t a s s i u m f e r r i c y a n i d e [K3Fe(CN)6], w i t h and w i t h o u t t h e a d d i t i o n o f NaOH t o m a i n t a i n . t h e pH a t 11.0?1.0. Dur ing t h e r e a c t i o n , s amples were t a k e n p e r i o d i c a l l y f o r a n a l y s i s and t h e pH was m o n i t o r e d . These t e s t s were a l s o conduc ted o v e r t h e t e m p e r a t u r e r a n g e o f 2 0 ° C t o 100°C. The a n a l y s i s o f t h e c h l o r i n a t e d samples r e q u i r e d t h e a d d i t i o n o f sodium s u l f i t e (Na2SO3) t o "quench" o r s t o p t h e r e a c t i o n by
I - I n e u t r a l i z i n g t h e c h l o r i n e .
I
C
36
e r e
b l e a c h f e r r i - 1 1 . 0 + 1 . 0 . 3°C t o zed f o r
i e l i t e r 3n ide n a i n t a i n t a k e n
l e s e t e s t ! t o l o o o c ,
l d i t i o n : t i o n by
. . . . . . . .. . . . .
M c t h o d o f C o s t A n a l y s i s
i:or ; i l l c u s t ; t t1 ; i lys i s ~ 0 1 . k ;i s i n g l c I i y p o t h c t i c a l p r o c e s s i n g lll;lclli~ic \vas u s e d . Tlic c h o s e n machine was a combined a v c r a g e of v a r i o u s p r o c e s s e s . These i n c l u d e : Kodacolor Color N e g a t i v e ( p r o c e s s C - 2 2 ) , E k t a c o l o r C o l o r Paper ( p r o c e s s E k t a p r i n t C), EktaChrOnle R e v e r s a l F i l m ( p r o c e s s E - 4 ) and Ektachrome Pape r ( p r o c e s s E k t a p r i n t - R ) . The f o l l o w i n g t a b l e shows t h e f l o w r a t e , c o n c e n t r a t i o n of sodium f e r r i c y a n i d e , and a p p r o x i m a t e cos t o f t h e i n d i v i d u a l b l e a c h e s and t h e "combined ave rage" .
R e p l e n i s h e r R e p l e n i s h e r Na3Fe ( C N ) 6 Bleach
Flow R a t e C o n c e n t r a t i o n 'Cost Proc.ess (m 1 / m i n) ( g / U $/IO0 g a l
Xodacolor (C- 2 2 ) 275
E k t a c o l o r Pape r (Ek t a p r i n t - C 260
Ektachrome Fi lm ( E - 4) 1 1 5
Ektachrome Pape r (Ek t a p r i n t - R) 150
Combined Average 2 0 0
25 $ 87.00
25 $ 48.00
120 $238.00
30
50
$ 72.00
$111.00
During f i l m p r o c e s s i n g a b o u t one s i x t h o f t h e r e p l e n i s r e r f e r r i c y a n i d e i s assume) t o b e r educed t o f e r r o c y a n i d e . An a v e r a g e y e a r was t a k e n as 260 d a y s a t e i g h t h o u r s p e r day . A "combined ave rage" machine was assumed t o h a n d l e 800 rolls of f i l m p e r day .
37
I
I SEC'1'ION VI
DISCUSSION OF IIESULTS
I ~
Analytical (Subprogram A )
Iodometric Determination of Ferricyanide
The concentration of sodium ferricyanide can be determined by reaction of ferricyanide with iodide ions forming f r e e i o d i n e , then titration of the iodine with standardized sodium thiosul- fate. The reactions involved are as follows:
2 Fe(CN)6-3 + 2 I- -+ 2 Fe(CN)g-4 + I 2 ( 2 8 )
Table I (page 40) shows the analysis of six samples of pqre sodium ferricyanide of various concentrations compared to the actual concentrations. The average deviation of the samples from the actual values is 0.48 g / l .
The test procedure was applied to an actual bleach solution from a Kodachrome K-12 processor to determine the precision of the test on a real sample. Seven analytical measurements of the same sample produced an average deviation of 0.83 g / 1 and a standard deviation of 1.02 g/l. Expressed as a percentage, the standard deviation is 0.95 percent of the average value for the concentration of sodium ferricyanide in a real bleach. This method of determining sodium ferricyanide concentration f o r qual- ity control of the photographic bleach is satisfactory. not sufficiently accurate for use in pollution control.
It is
Cerimetric Determination of Sodium Ferrocyanide
The concentration of sodium ferrocyanide can be determined from it oxidation in acid solution by means of a standardized ceric sulfate solution with sodium diphenylamine-sulfonate as an indi- cator; the reaction being:
~ e + 4 + Fe(CN)6-4 -+ ~ e + ~ + Fe(CN)6 (30 1 -3
Table I1 (page 41) shows the results of five samples using this method of analysis. The titration end point is difficult to observe; especially on used photographic bleach solutions. This data shows an average deviation of k2 .13 g / l . This test method is also acceptable for use as a rapid quality control measurement, but is not satisfactory for pollution control use.
39
TABLE I
S amy 1 e
A
B C
D
E
F
Sodium Ferricyanide (Na3Fe(CN),6) Concentrations
as Determined by Iodometric Titration Methods Sod
Sodium Ferricyanide Concentration Sample
Actual (g/ 11 Measured ( g / l )
1 0 . 0 0
1 0 . 0 0
2 0 . 0 0
3 0 . 0 0
3 5 . 0 0
A 1 0 . 2 6
8 . 4 8
2 0 . 0 4
B
C
3 0 . 1 6
3 4 . 5 6
50.00 4 9 . 5 5
D
E
40 L
i
TABLE I 1
Sodium F e r r o c y a n i d e (Na4Fe ( C N ) 6 1 0 H 2 0) C o n c e n t r a t i o n as
Dctcri:iiiicJ by Ccyimctric Titration Method
Sodium F e r r o c y a n i d e C o n c e n t r a t i o n
A c t u a l ( g / l ) Measured ( g / l )
2 0 . 0 0 19.94
30.00
50.00
70.00
80 .00
3 1 . 1 1
52.20
66 .04
76.45
l )c te r111innt io~z o f F e r r o c y a n i d e u s i n g S p c c t r o p h o t o m e t r i c masure,
nicnt a t 7 0 0 nm.
The c o n c e n t r a t i o n o f sodium f e r r o c y a n i d e (Na4Fe (CN)6*10 H20) 3 c a n be d e t e r m i n e d by a d d i n g f e r r i c i o n t o form Fe4 [Fe(CN)6]
P r u s s i a n B lue ; and m e a s u r i n g t h e a b s o r b a n c e o f t h e s o l u t i o n at 7 0 0 m p ( F i g u r e 1 0 , page 4 3 ) .
F i g u r o 11 (gage 4 4 ) and F i g u r o 12 (page 4 5 ) show t h e absorb.. a n c e - - c o n c e n t r a t i o n c u r v e s a t 700 mp f o r t h e f e r r o c y a n i d e con. c e n t r a t i o n r a n g e s 0-1 mg/l and 0 -25 mg/ l , r e s p e c t i v e l y . These c u r v e s show t h a t o v e r t h e above c o n c e n t r a t i o n r a n g e s , t h e r e - l a t i o n s h i p i s l i n e a r .
A l e a s t s q u a r e s a n a l y s i s was made on b o t h o f t h e above f i g u r s, For t h e c o n c e n t r a t i o n r a n g e 0-25 mg/l f e r r o c y a n i d e ; Fe(CN)6’ .
as = 0 , 0 0 3 6
- .
2
a = 0.0522 1 S t a n d a r d E r r o r o f Absorbance S = k O . 0 0 8
Y ‘
F o r t h e c o n c e n t r a t i o n r a n g e 0 - 1 mg/l f e r r o c y a n i d e ; Fe(CN)6 - 4 a, = 0 , 0 0 6 3
a l = 0.0522
S t a n d a r d E r r o r o f Absorbance S = k O . 0 0 1 0 2 Y
T h i s method o f a n a l y s i s f o r f e r r o c y a n i d e i s e x t r e m e l y a c c u r a t e ; k
and can b e used t o d e t e r m i n e t h e c o n c e n t r a t i o n o f f e r r o c y a n i d e f i n t h e r a n g e o f 0 . 2 t o 0 . 4 mg/l a s r e q u i r e d f o r p o l l u t i o n con- : t r o l measurements .
D e t e r m i n a t i o n o f F e r r i c y a n i d e u s i n g S p e c t r o p h o t o m e t r i c Measure-;. l
ment a t 4 1 7 XI.,.
The COI:<.L l L L ~ . , s B . J ~ , U i u i n f e r r i c y a n l d c can be d e t e r m i n e d d i r e c t l y b y ~ l i ~ L I s ~ r c l , r c ~ ~ t o f i t s a b s o r b a n c e a t 4 1 7 m u . The f o l l o w i n g a b s o r b a n c e - c o n c e n t r a t i o n v a l u e s were o b t a i n e d f o r sodium f e r r i c y a n i d e a t 4 1 7 mp:
u c rj P h 0 m P 4
Fi
WAVELENGTH ABSORBANCE
500 ,049 6 20 .067 640 ,06
6 8 0 , 0 9 4 700 ,095 7 2 0 .09 5 7 3 0 .09 5 7 4 0 ,093
7 8 0 ,083 800 ,077
660 ,087
7 6 0 . o m
0 -600 620640 660 680 700 720 740 760 780 800 Wavelength, m p
Figure Q O Absorbance Curve for Prussian Blue
.O 45
.04 0
,03 5
.03 0
.O 25 0
(d 2 ,020 P k 0 P v1 ,015
,010 <
.oo 5
0 o a I ,2 .3 .4 .5 .6 .7 .8 9 ID
Total Fe(CN)6 Concentration mg/l
Figure 11 Absorbance--Total F e ( C N ) 6 Concentration from
0.0 to 1.0 mg/liter at 700 mp
4 4
1.2
1 .I
1 .O
.9
,8
.7
.6
.5 Q, u cd .4
v, O .3 P k
P 4 .2
.I
0 0 2 4 G 8 IO 12 14 16 18 20 22 24 26 28
lotal Fe(CN) Concentration (mg/l) t 6 ID
b E:
Figure 12 Absorbance--Total Fe(CN) 6 Concentration From
0.0 to 25.0 m g / l a t 7 0 0 mP
4 5
Con c e 11 t I* a t i o 11 of Sod i uln 1: c 1' r i cy a n i de
gm/ 1
' 0 , 4 2 9 0 . 2 7 ' 3 0 . 2 1 5 0 . 0 8 6 0 . 0 4 3 0 . 0 0 8
Absorbancc
1 . 5 1 2 1.000
0 . 3 1 6 0 . 1 6 0 0 , 0 2 6
0 . 7 ~ 8
A l e a s t s q u a r e s a n a l y s i s on t h i s d a t a r e s u l t s i n t h e f o l l o w i n g :
a, = 0 . 0 1 6
a = 3 . 5 0 1 S t a n d a r d E r r o r o f Absorbance S = 5 0 . 0 6 3 1
Y Th i s method i s s a t i s f a c t o r y f o r m e a s u r i n g t h e c o n c e n t r a t i o n o f sodium f e r r i c y a n i d e i n s o l u t i o n s c o n t a i n i n g o n l y f e r r o - a n d f e r r i - c y a n i d e . I t i s n o t s u i t a b l e f o r p h o t o g r a p h i c b l e a c h s o l u t i o n s (due t o c o l o r i n t e r f e r e n c e ) o r o t h e r s o l u t i o n s where t h e concen- t r a t i o n i s l e s s t h a n 1 0 . 0 0 m g l l a s Na3Fe(CN)6
D e t e r m i n a t i o n o f Sodium F e r r i c y a n i d e u s i n g S p e c t r o p h o t o m e t r i c
Neasurement a t 4 6 0 . 5 m u .
The c o n c e n t r a t i o n o f sodium f e r r i c y a n i d e c a n be d e t e r m i n e d i n a h i g h e r c o n c e n t r a t i o n r a n g e 0 - 4 gm/l by d i r e c t measurement of i t s a b s o r b a n c e a t 4 6 0 . 5 m P . The f o l l o w i n g a b s o r b a n c e - c o n c e n t r a - t i o n v a l u e s were o b t a i n e d f o r sodium f e r r i c y a n i d e a t 460 .5 m P e . _
C o n c e n t r a t i o n Sodium F e r r i c y a n i d e
gm/ 1
2 . 6 6 1 . 7 0 1 . 3 3 1 . 3 3 0 . 8 5 0 . 4 2 6 0 . 3 4 5 0 . 2 5 5 0 . 1 7 0 0 . 0 8 5
4 6
Absorbance
0 . 6 7 3 0 . 4 3 5 0 . 3 3 7 0 . 3 3 5 0 , 2 2 2 0.115 0 , 0 9 5 0 . 0 7 0 0 , 0 5 0 0.024
ri-
n-
l e a s t s q u a r c s a n a l y s i s r e s u l t s i n t h c f o l l o w i n g :
a. = 0.0056
= 0 . 2 5 1 "1 S t a n d a r d E r r o r o f Absorbance S = k O . 0 1
Y T h i s method i s s i m i l a r t o t h e measurement a t 4 1 7 mp,but c a n b e used i n a h i g h e r c o n c e n t r a t i o n r a n g e .
Nitropruss i ( I C T I I ~ ~ ~ I - ! ~ ; ~ ~ ( I ~ c I ~ c ( I ; O ( C N ) g ~ ~ ) - -
I t NJS i oL ; ! i J L\:L:J), i 11. ; ; l i s w o r k t h a t m a t e r i a l b a l a n c e s u s i n g s p e c t r o s c o p y r e su l t cc i i n an o v e r a l l complex c y a n i d e i n c r e a s e o f t h e t r e a t e d s o l u t i o n . I t was s u s p e c t e d t h a t some i n t e r f e r - ence o f a n i n t e r m e d i a t e o x i d a t i o n p r o d u c t be tween f e r r o c y a n i d e and f e r r i c y a n i d e was t h e c a u s e o f a n i n c r e a s e d abso rbance o f t h e t r e a t e d s a m p l e s . The n i t r o p r u s s i d e i o n was p roposed a s t h e i n t e r m e d i a t e . ( 1 6 ) S e v e r a l t e s t s were c o n d u c t e d u s i n g f e r r o - and f e r r i c y a n i d e w i t h a known q u a n t i t y o f n i t r o p r u s s i d e (Tab le 111, page 4 8 ) . I f t h i s i n t e r m e d i a t e had a g r e a t e r a b s o r b t i v i t y a t t h e a b s o r b a n c e r e a d i n g s f o r f e r r o - a n d f e r r i c y a n i d e , i t would e x p l a i n t h e m a t e r i a l b a l a n c e problem. The r e s u l t s ( T a b l e IXX) c o n f i r m t h e i n t e r f e r e n c e o f t h i s compound by showing t h a t n i t r o - p r u s s i d e w i l l p r o d u c e t h e e f f e c t o f a h i g h e r complex c y a n i d e c o n c e n t r a t i o n t h a n i s p r e s e n t .
47
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ll th
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48
E l e c t r o l y s i s o f F e r r o c y a n i d e s
8 (Subprogram B) 1 b h
~ o n - i \ l c ~ n b r a n e C e l l ; Ambient Tempera tu re 4
~ 1 1 c e l l s p r e p a r e d f o r t h i s s t u d y were compared t o a t h e o r e t i c a l c e l l d e f i n e d t o a c c o u n t f o r t h e anode r e a c t i o n o n l y . tile v a r i a b l e s i n v o l v e d t o c u r r e n t and t i m e , a l l c e l l s were cha rged I q i t h s o l u t i o n s of i d e n t i c a l f e r r o c y a n i d e c o n c e n t r a t i o n . A t any c u r r e n t t h e r e i s a t ime i n which a t h e o r e t i c a l c e l l p r o d u c e s a 1 0 0 % c o n v e r s i o n ( f e r r o - t o f e r r i c y a n i d e ) . Thus , t h e c e l l s c a n b e compared on a d i m e n s i o n l e s s t i m e s c a l e d e f i n e d a s a p e r c e n t of t h e t h e o r e t i c a l c o n v e r s i o n t i m e .
To l i m i t
e =t (31 ) t C
l a e r e 0 = P e r c e n t of t h e o r e t i c a l c o n v e r s i o n
t = A c t u a l t ime o f t h e r e a c t i o n ( m i n u t e s )
t c = T h e o r e t i c a l t ime f o r 1 0 0 % c o n v e r s i o n ( m i n u t e s )
The p e r c e n t o f c o n v e r s i o n by e a c h c e l l a t 6 = 1 was d e s i g n a t e d as t h e e f f i c i e n c y o f t h e c e l l .
F i g u r e 13 (page 5 0 ) shows t h e r e l a t i o n s h i p be tween t h e con- v e r s i o n of f e r r o c y a n i d e and t h e p e r c e n t o f t h e o r e t i c a l c o n v e r s i o n , f o r v a r i o u s c a t h o d e t o anode c u r r e n t d e n s i t y r a t i o s ( C D R ) . A s t h e c u r r e n t d e n s i t y r a t i o i n c r e a s e s , c o n v e r s i o n i n c r e a s e s . T h i s conf i rms t h e t h e o r y t h a t i n c r e a s i n g hydrogen o v e r v o l t a g e o f t h e ca thode (hydrogen e v o l u t i o n p e r u n i t a r e a o f c a t h o d e ) i n c r e a s e s t h e o v e r a l l o x i d a t i o n e f f i c i e n c y r e l a t i v e t o F a r a d a y ' s Law. Although CDR's <1 were e v a l u a t e d e x p e r i m e n t a l l y , t h e y were n o t i n c l u d e d i n F i g u r e 13 b e c a u s e d e c o m p o s i t i o n of t h e complex o c c u r s . No p i l o t p l a n t c e l l was , t h e r e f o r e , d e s i g n e d w i t h a C D R < l .
F igu re 1 4 (page 5 1 ) compares t h e c u r r e n t d e n s i t y r a t i o and ' c o n v e r s i o n a t 0 = 1. A t t h i s Q v a l u e , t h e maximum i n c u r r e n t
usage h a s b e e n r e a c h e d , For 0< 1, f u l l c o n v e r s i o n h a s n o t b e e n ' a t t a i n e d . For 0> 1, power e f f i c i e n c y i s r e d u c e d i d u e t o an i n -
crease i n t h e s e c o n d a r y c a t h o d e r e a c t i o n r e l a t i v e t o t h e p r i m a r y anode r e a c t i o n . Using t h e method of l e a s t s q u a r e s , t h e . fo l low- i n g e x p r e s s i o n was de r ived . '
(32$ 1 .152 -1 C o n c e n t r a t i o n of F e r r o c y a n i d e
In X, = [-0.744€DR 1 Where X O = c o n v e r s i o n = 1 - a t 0 = 1 . 0
I n i t i a l c o n c e n t r a t i o n i e r r o c y a n i d e
CDR = Cathode- to-Anode C u r r e n t D e n s i t y R a t i o
S t a n d a r d d e v i a t i o n ( a v e r a g e e r r o r ) i s 4 . 3 2 9
49
0 a *d c cb x u 0 k k 0 F4
3 c) c, k 0 > c 0 u c 3
Q d 0 V k Q) a
100
95
9 0
85 8 0
75
70
6 5
6 0
5 5
5 0
4 5
40
35
3 0
2 5
20
15
10
5 0 I
.20 ,4 0 .60 .8 0 I .oo 1.20 1 4 0 0
P e r c e n t T h e o r e t i c a l Conversion
F i g u r e 1 3 : ~ , ' . , 1 I 1 (-t~:-.i:~.:cJ F c r r o c y a n i d c - - P e r c e n t T h e o q t i c a l
,\dn-I\:cinbrane E l e c t r o l y s i s a t V a r i o u s Convcl-s i o i i
C u r r e n t D e n s i t y R a t i o s
1.4 0
1
I I 0 W
0 .2 .4 .6 .8 LO 1.2 1.4 1.6 1.8 2.0 24 2.6 2.6 3.0 3,2 La& c m
Figure 14 Effect of Current Density Ratio on Conversion
of Ferrocyanide to Ferricyanide in an Electrolytic Cell
For any r e q u i r e d c o n v c r s i o n , u s e of t h e abovc e x p r e s s i c n w i l l show t l ic niaximum c u r r e n t d e n s i t y r a t i o f o r optimum c u r r c n t u t i 1 i z a t i on .
F i g u r e 1 5 (page 5 3 ) shows t h e r e l a t i o n s h i p be tween t h e c u r r c n t d e n s i t y r a t i o and t h e i n c r e a s e i n o x i d a t i o n r a t e w i t h t empcra - t u r e , o v e r t h e r ange from 2 5 ° C t o 6 0 ° C . of a n a l y s i s p roduced t h e f o l l o w i n g e q u a t i o n :
The l e a s t s q u a r e s mcthod
1,839 - ,0281 ( C D R ) A T
Where A R = P e r c e n t change i n r a t e
A T = Change i n t e m p e r a t u r e (C")
( 3 3 )
S t a n d a r d D e v i a t i o n i s 3 . 6 0 %
Using t h i s e q u a t i o n , t h e r a t e i n c r e a s e c a n be c a l c u l a t e d f o r a s e l e c t e d c u r r e n t d e n s i t y r a t i o and t e m p e r a t u r e above 25°C.
The Membrane C e l l : Ambient Tempera ture
?'he membrane c e l l s were compared u s i n g t h e p e r c e n t o f t h e o r e t i c a l c o n v e r s i o n , 0 , i n t h e same manner a s was done f o r t h e non-mem- b r a n e e l e c t r o l y t i c c e l l s . F i g u r e 1 6 (page 5 4 ) shows t h e r e - l a t i o n s h i p be tween t h e p e r c e n t t h e o r e t i c a l c o n v e r s i o n and t h e a c t u a l c o n v e r s i o n i n t h e membrane c e l l . I t was found t h a t t h e membrane c e l l was a b l e t o a f f e c t n e a r l y 1 0 0 % c o n v e r s i o n o f f e r r o - c y a n i d e t o f e r r i c y a n i d e . D e v i a t i o n s of t h e a c t u a l c u r v e from t h e t h e o r e t i c a l c u r v e were p r i m a r i l y due t o v a r i a t i o n s i n t h e c u r r e n t w i t h time. As t h e r e a c t i o n p r o c e e d e d , t h e c u r r e n t de-' c r e a s e d s l i g h t l y due t o t h e d e c r e a s e i n f e r r o c y a n i d e c o n c e n t r a t i o n . T h i s was compensa ted f o r i n t h e a n a l y s i s by u s i n g t h e a v e r a g e c u r r e n t t o c o n s t r u c t t h e F a r a d a y ' s Law p l o t .
The e l e v a t e d t e m p e r a t u r e s t u d i e s were c o n d u c t e d be tween 2 5 O C and 50°C. The r e s u l t i n g r e l a t i o n s h i p be tween c u r r e n t and temp- e r a t u r e a t a c o n s t a n t a p p l i e d p o t e n t i a l i s shown i n F i g u r e 1 7 (page 5 6 ) . The e q u a t i o n f o r t h e s l o p e o f t h i s curve was f o u n d t o b e :
Where A I = change i n c u r r e n t (amps)
A T = change i n t e m p e r a t u r e ("C)
No change i n t h e f i n a l c o n v e r s i o n ( = l o o % ) r e s u l t e d a t t h e e l e - v a t e d t e m p e r a t u r e .
5 2
F: b, V
U .rl c,
c, c Q, u k Q P( v
t
od
i
ical -
e rro-
- - ation,
!? - Ind
8 -
3 .o
2.5
2.0
I .5
I ,O
.5
0
Figure 15 Effect of Current Density Ratio on Ferrocyanide .-
Oxidation Rate for Non-Membrane Electrolytic Cell
53
. -- . . . . . . . . . I I 1 I I
0 e,
Q, 3 .rl c rd x U 0 k !4
a, c4 rw 0
VI c C .d VI k a, > c 0 u r( tu U .d c, Q, k 0 Q, c
i- a c cd
r(
6 3 c, u < Q,
.G e,
w 0
c: 0 v, .d k (3 a E 0 U
9 r(
0) k 3 M
.rl c4
d r( Q) u u .rl tJ x 4 0 k e, U a, r(
w Q, a h fi 0 c 03 k
D E Q,
rd
c .rl
a w . v i
c rj x U
.rl k k Q) c4
54
,3 5
.3 0
E 2.20
.IO
Temper a ture ("C)
Figure 17 Current-Temperatute Relationship for a Membrane
Type Electrolytic Cell
!
The ca rbon anodes w e r e found t o flake and decompose during t h e r e a c t i oii . P i l o t P l a n t C e l l
A c o n t i n u o u s f l o w e l e c t r o l y t i c o x i d a t i o n c e l l was d e s i g n e d from t h e r e s u l t s o f t h e bench t o p work on t h e non-membrane c e l l . A c e l l t h a t would p roduce a 9 6 % c o n v e r s i o n o f f e r r o c y a n i d e t o f e r r i - c y a n i d e was c h o s e n . From e q u a t i o n (32 ) i t was found t h a t a c u r r e n t d e n s i t y r a t i o o f 2 0 . 3 t o 1 . 0 would p r o d u c e t h i s c o n v e r s i o n w i t h t h e l e a s t amount o f power l o s s .
T a b l e I V (page 5 7 ) i s a compar i son of t h e a v e r a g e r e s u l t s o f t h e p i l o t e l e c t r o l y t i c c e l l s t u d i e s w i t h r e f e r e n c e t o t h e t h e o r e t i c a l c o n v e r s i o n (computed f r o m F a r a d a y ' s Law). The a c t u a l v e r s u s t h e t h e o r e t i c a l c o n v e r s i o n a g r e e s w e l l a t t h e h i g h e s t f l o w r a t e , b u t t h e r e l a t i o n s h i p d e c r e a s e s w i t h d e c r e a s i n g f l o w . D e c r e a s e s i n c e l l c o n v e r s i o n e f f i c i e n c y from t h e d e s i g n maximum of 9 6 % a r e a t t r i b u t e d t o :
- 1 , ~ , . . L t i c s i n anode c y l i n d r i c a l s h a p e
- p o i n t s o ~ 1 r c c s o f h i g h c u r r e n t d e n s i t y on anode
E x t e r n a l a g i t a t i o n , e f f e c t e d by b u b b l i n g a i r t h r o u g h t h e co lumns , produced n o . n o t i c e a b l e change i n c e l l c o n v e r s i o n . hydrogen e v o l u t i o n a t t h e c a t h o d e p roduced s u f f i c i e n t a g i t a t i o n f o r b o t h e l e c t r o d e s .
A p p a r e n t l y ,
C o s t A n a l y s i s f o r E l e c t r o l y t i c R e g e n e r a t i o n o f B leach
F o r an a v e r a g e p r o c e s s i n g mach ine , b l e a c h r e g e n e r a t i o n w i l l b e c a r r i e d o u t on a c o n t i n u o u s flow b a s i s w i t h t h e r e q u i r e d f e r r i - c y a n i d e a d d i t i o n and pH a d j u s t m e n t a f t e r r e g e n e r a t i o n . S i n c e o n e - s i x t h o f t h e f e r r i c y a n i d e i s c o n v e r t e d t o f e r r o c y a n i d e d u r i n g t h e b l e a c h i n g p r o c e s s , t h a t amount must b e r e g e n e r a t e d . E l e c t r o - l y t i c a l l y , t h a t r e q u i r e s 4 4 amperes /hour , p e r e i g h t hour day on t h e "combined ave rage" machine o v e r f l o w . A p r o d u c t i o n f l o w s c h e m a t i c f o r t h e e l e c t r o l y t i c sys t em i s shown i n F i g u r e 1 8 ( p a g e 59 ) . A summary o f equipment c o s t ' e s t i m a t e s f o l l o w s :
56
i o n u i l d r a t - e o f r r o - ferric d i z e d it on
h e
rom A ferri- current i th
f the tical the but in 2
imns , 7 9
ion
le i-
iring :tro- on
'age
TABLE IV
CONVERSION EFFICIENCY OF
PILOT PLANT NON-MEMBRANE ELECTROLYTIC CELL
(Initial Solution Concentration:
(Applied Voltage: 5 . 5 VDC
Applied .Flow Rate Current (m 1 /mi n) (amperes) .
300
2 0 0
150
300
5 . 2
5 . 0
5.0
6.0
57
5.03 g / 1 Fe(CN),-4)
Temperature: Ambient)
Calculated Experimental Theoretical Conversion Conversion
(%) (Faraday's Law) (9)-
42.9 4 1 . 0
5 5 . 5
56 .2
4 6 . 2
6 5 . 5
8 7 . 4
47.1
Equipment
E l e c t r o l y t i c c e l l w i t h pumps f o r r e c i r c u l a t i o n
50 g a l l o n p o l y e s t e r tank
Mixer 2 hp , r u b b e r c o a t e d s t e e l
pH c o n t r o l l e r w i t h p r o b e , s o l e n o i d and m e t e r i n g v a l v e
Labor and ma in tenance ( e s t i m a t e d a t 1 0 % i n s t a l l e d c o s t )
c o s t - $1 ,500
$ 1 0 0
$ 950
$3,000
$ 555
T o t a l $ 6 , 1 0 5 ,
C a l c u l a t e d p r e s e n t b l e a c h c o s t p e r 8 h r . day : C o s t of E l e c t r o l y t i c Equipment ( p e r day f o r 1 0 y e a r amor t iza t io$ :$Z.18 Savings f o r a 9 0 % b l e a c h r e c o v e r y : Dai ly s a v i n g s = D a i l y b l e a c h s a v i n g s - D a i l y Cost o f Equipment =
Sav ings p e r r o l l @800 r o l l s / d a y = 2 . 9 4 / r o l l
$28 .20
$25 .40
$ 2 5 . 4 0 - $ 2 . 1 8 = $23.22
E
sa
Sys t em
Bleach f rom Processor
E l e c t r o l y t i c Cell
S t i r r e r
bs Mixing and Replenishing Tank
er
Figure 18 Schematic of an Electrolytic Bleach Regeneration
System
5 9
Ozonc R c g c n c r a t i o n and Dccomposi t ion o f Complex Cyanides
(Subprogram C )
Bench T o p R c g c n e r a t i o n
The r e s u l t s o f two bench t o p r e g e n e r a t i o n s t u d i e s a r e shown i n F i g u r e 1 9 (page 6 1 ) . be tween p e r c e n t of c o n v e r s i o n ( F e r r o c y a n i d e t o f e r r i c y a n i d e ) and t ime o z o n a t i o n . s q u a r e s a n a l y s i s f o r ozone t r e a t m e n t w i t h o u t pH c o n t r o l . s l o p e i s d e s c r i b e d by t h e f o l l o w i n g e q u a t i o n :
These c u r v e s show a l i n e a r r e l a t i o n s h i p
The upper curve i s t h e r e s u l t o f a l e a s t The
&.here x = Co - C t ~0 a n d Co = C o n c e n t r a t i o n of ferrocyanide
C t = C o n c e n t r a t i o n of -ferrocyanide a t t i t
a t t = o
I n molar u n i t s , t h i s e q u a t i o n becomes
[GI = Molar ozone f l o w r a t e (moles /minu te )
The lower cu rve i n F i g u r e 1 9 i s t h e r e s u l t of a l e a s t s q u a r e s a n a l y s i s o f t h e o z o n a t i o n r e a c t i o n w i t h t h e pH c o n t r o l I e d be tween 5 . a K 2 S . XJ n o t i c e a b l e change i n t h e o x i d a t i o n r a t e o c c u r e d I C i z h 3: ~ i i t h o : ~ t p i i c o n t r o l . i r i c r zzse i:i ti;? JcLIrcc o f c o n v e r s i o n , when t h e pH was c o n t r o l l e d .
The o n l y e f f e c t n o t e d was a s l i g h t
S ince t h c L ; ~ c ; L ~ c ~ : i . - , . c ~ ~ a r e t y p i c a l f o r z e r o o r d e r r e a c t i o n s , t h e r a t e o f o s i d a t i o l l o f f e r r o - t o f e r r i c y a n i d e i s i t h ozone i s zero o r d e r w i t h r e s p e c t t o t h e f e r r o c y a n i d e c o n c e n t r a t i o n , o x i d a t i o n r e a c t i o n i s e x t r e m e l y r a p i d and t h e mass t r a n s f e r of ozone i n t o t h e s o l u t i o n i s t h e r a t e c o n t r o l l i n g p a r a m e t e r ,
The
6 0 I
de
de
les)
.60
IO Time, Min.
Figure 19 Conversion--Time Curve for Ozone Regeneration
61
' !
A compar ison o f t h e expe r in i cn ta l r e s u l t s and t h e s t o i c h i o - m e t r i c c q u a t i o n f o r t h e r e a c t i o n i s shown i n T a b l e V (page 6 3 ) . The s t o i c h i o m e t r i c e q u a t i o n i s g i v e n by:
2 Na4 Fe(CN)6 1 0 H 2 0 + 03 * 2 Na3 Fe(CN)6 + 2 NaOft + 02 4
19 H 2 0 ( 3 7 )
For e v e r y u n i t w e i g h t o f ozone , 2 0 . 2 u n i t w e i g h t s o f f e r r o - c y a n i d e a r e o x i d i z e d t o 1 1 . 7 u n i t weights of f e r r i c y a n i d e . (The u n i t of w e i g h t can be grams, pounds , t o n s , o u n c e s , e t c . ) . The o x i d a t i o n e f f i c i e n c y o f ozone (Tab le V page 63) i s approx- i m a t e l y 1 0 0 % f o r c o n c e n t r a t i o n s o f f e r r o c y a n i d e above a b o u t one gram p e r l i t e r . Below t h a t c o n c e n t r a t i o n , ozone i s r e - l e a s e d from t h e s o l u t i o n and t h e f e r r i c y a n i d e complex b e g i n s t o s l o w l y decompose. Thus, e x h a u s t e d ozone i s a n i n d i c a t o r o f t h e r e a c t i o n end p o i n t .
A s e r i e s o f t e s t s were c o n d u c t e d w i t h u s e d p h o t o g r a p h i c ' b l e a c h -
These t e s t s were conduc ted t o d e t e r m i n e t h e e f f i c i e n c y o f t h e c o n v e r s i o n o f f e r r o - t o f e r r i c y a n i d e , u s i n g ozone on a c t u - a l b l e a c h s o l u t i o n s . T a b l e V I (page 6 4 ) shows t h a t t h e r e i s no a p p a r e n t d e c r e a s e i n t h e ozone o x i d a t i o n e f f i c i e n c y f o r a c t u a l o r s i m u l a t e d p h o t o g r a p h i c b l e a c h e s .
' e s f rom Ektachrome ME-4 and Kodachrome K-12 p r o c e s s o r s .
A t p r e s e n t , t h e r e a r e a number of t e l e v i s i o n news p r o c e s s i n g l a b o r a t o r i e s and commercial p h o t o f i n i s h e r s u s i n g an ozone b l e a c h r e g e n e r a t i o n sys t em. Some o f t h e f e r r i c y a n i d e b l e a c h e s have b e e n r e g e n e r a t e d up t o f o r t y times w i t h no o b s e r v e d a d v e r s e e f f e c t s i n t h e b l e a c h i n g p r o c e s s .
P i l o t P l a n t R e g e n e r a t i o n
For a n a l y z i n g a c o n t i n u o u s f l o w column . r e a c t o r , t h e f o l l o w i n g r e l a t i o n s h i p was u s e d : ( 1 s )
Where G = Molar f l o w of g a s p e r s q u a r e f o o t o f r e a c t o r cross s e c t i o n moles
?vE
62
tu t 1 I t ry
TABLE V
COMPARISON OF EXPERIMENTAL RESULTS TO STOICHIOblETRIC CALCULATIONS
FERROCYANIDE OXIDATION WITH OZONE
Volume of Solution: 1 Liter
Concentration of Sodium Ferrocyanide:
Ozone Feed Rate 2.36 g/hr
11.45 g/1
Na3 Fe(CN)6 Conc. ( g / l ) Time of Reaction
Measured Theoretical Me as u r ed T h e o r e t i c a l
a u n 2: a d L? 0 e 0 3: 14
R w cn 3
k w 0
n
, " I C
6 4
Yo, Y1 - bloIcs of ozone per mole of air at the i n l e t and a t any point in the reactor, rcspectively.
L blolar upward flow of liquid per square foot o f reactor cross section Moles
ftzhr
X o , X1 = Moles of ferrocyanide per mole of water at the inlet (X ) and at any point in the reactor (XI?
ferrocyanide converted per mole of ozone = 2.0
b = Stoichiometric constant for moles of
For a very rapid reaction (ozone with ferrocyanide),the molar concentration of ozone at the outlet of the column is zero at equilibrium and under proper design. For convenience, the change in the concentration of ferrocyanide is expressed by the following convention:
Where C = The percent of conversion of ferrocyanide to ferricyanide
Upon substitution of equation ( 3 8 ) into equation ( 3 9 ) the relationship becomes:
G b
[Yo - YIJ = L X o C (40)
The liquid flow function L can be expressed as a constant (k) times the flow rate ( v ) , or
L = kv (41)
SubstitutjnE tI; i 5 i i i t o equation (40) yields
6 5
G [ Y o - Y1] = kv X o C b
(42)
For t h e s y s t e m under i n v e s t i g a t i o n , a l l t h e te rms i n equa - t i o n ( 4 2 ) e x c e p t f o r t h e l i q u i d f l o w r a t e u and C a r e con- s t a n t s t h e r e f o r e ;
o r
. T h i s shows t h a t t h e r a t e o f c o n v e r s i o n o f f e r r o c y a n i d e t o f e r r i c y a n i d e i s i n v e r s e l y p r o p o r t i o n a l t o t h e f l o w r a t e o f s o l u t i o n ( a t a c o n s t a n t ozone f e e d r a t e ) . The ozone o u t - p u t c o u l d n o t be v a r i e d w i t h t h e g e n e r a t o r employed i n t h i s s t u d y . A g r a p h i c a l i n t e r p r e t a t i o n of t h i s r e l a t i o n - s h i p and t h e e x p e r i m e n t a l d a t a a r e shown i n F i g u r e 2 0 , E x p e r i m e n t a l r e s u l t s a g r e e w e l l w i t h t h e t h e o r e t i c a l c u r v e , e x c e p t a t low f l o w r a t e s . The e r r o r a t t h e l o w f l o w r a t e s i s p r o b a b l y due t o f l u c t u a t i o n s i n f l o w . t h e p i l o t p l a n t work was ozone e x h a u s t e d f r o m t h e r e a c t i o n co lumns .
A t no p o i n t d u r i n g
C o s t A n a l y s i s f o r Ozone O x i d a t i o n o f F e r r o c y a n i d e t o F e r r i - 7 '
c v a n i d e f o r B leach Reuse
For r e g e n e r a t i o n of t h e "combined a v e r a g e " p r o c e s s o r f e r r i - c y a n i d e b l e a c h s o l u t i o n w i t h ozone , a t e n gram p e r h o u r ozone g e n e r a t o r i s r e q u i r e d , A flow s c h e m a t i c is shown i n F i g u r e 2 1 (page 6 8 ) .
66
67
P
HBr Tank
pti Controller
i E 2 Solenoid Valve I
1 1 - Bleach Feed
c P H Probe To
Storage
I Ozone
I Generator
1 I Sparger system
Figure 21 Flow Schematic of a Photographic Bleach
Regeneration System Using Ozone
6 8
process o v e r f l o w b lcac l l f l o w s t o t h c r e a c t o r vessel f o r ozonc l - c g e i i c r a t i o n . S i n c e a l l b l e a c h o s i n t h e p h o t o g r a p h i c p r o c c s s 31-e u s e d a t a pH r a n g e of 7 t o 9 , hydrobromic a c i d i s mc tc rcd i l l t o t h e v e s s e l t o c o n t r o l t h a t pH r a n g e . A f t e r r e g e n e r a t i o n t h e b l e a c h i s pumped t o a h o l d i n g t a n k f o r r e u s e . The c o s t o f equipment i s l i s t e d be low:
Equipment
Ozone Generator
c o s t
$ 2 , 0 0 0
Dry A i r Supply Sys tem $ 350
50 G a l l o n P o l y e s t e r Tank $ 1 0 0
Mixer : 2 lip r u b b e r - c o a t e J s ; t c c l
S p a r g e r s a i l c i .!< L * b , 1 , I : ) ;
Pumps
pH c o n t r o l l e r w i t h a u t o m a t i c p r o b e , s o l e n o i d and m e t e r i n g v a l v e
Labor and Main tenance ( e s t i n a t e d a t 1 0 % c o s t )
$ 550
$ 3 0 0
$ 250
$3,000
$ 6 5 0
T o t a l $ 7 , 2 0 0
C a l c u l a t e d p r e s e n t b l e a c h c o s t p e r 8 h o u r day : Cos t o f ozone equipment ( p e r day for 1 0 y e a r a m o r t i z a t i o n ) : Sav ings f o r a 9 0 % b l e a c h r e c o v e r y : $ 2 5 . 4 0 D a i l y s a v i n g s = D a i l y b l e a c h s a v i n g s - D a i l y C o s t equipment =
S a v i n g s p e r r o l l @ 8 0 0 r o l l s p e r day = 2,854 p e r r o l l
$28 .20 $2.50
$ 2 5 . 4 0 - $ 2 . 5 0 = $22 .90
Bench Top D e s t r u c t i o n
69
The r e s u l t s o f t h e ozone d e s t r u c t i o n a t ambien t t e m p e r a t u r e a r e shown i n Tab le V I 1 (page 7 0 ) . Only minor changes i n t h e t o t a l c o n c e n t r a t i o n o f complex c y a n i d e r e s u l t e d d u r i n g o z o n a t i o n of t h e s t a n d a r d b l e a c h s o l u t i o n a t room t e m p e r a t u r e . Dur ing a l k a - l i n e o z o n a t i o n , t h e s o l u t i o n became d a r k r e d a f t e r t h e s t o i c h i o - m e t r i c amount o f ozone ( f o r t o t a l c y a n i d e d e s t r u c t i o n ) had been added t o t h e s o l u t i o n .
'
t h e f o r m a t i o n o f s m a l l amounts o f t h e r e d F e r r a t e i o n ( F d = ) , s i n c e t h e c o l o r d i s a p p e a r e d upon a c i d i f i c a t i o n of t h e sampfe . F e r r a t e i o n i s s t a b l e o n l y i n b a s i c s o l u t i o n s .
T h i s c o l o r a t i o n may have b e e n due t o
1
/ I
7" i
I
TABLE V I 1
RESULTS OF OZONE DESTRUCTION OF FERROCYANIDE
AT AMBIENT TEMPERATURE
Initial Time of Final Complex Ozona t ion Complex Average
Concentration (min) Concentration PH
1. 6 . 3 5 r t 0 . 0 1 6 0
2 . 5 . 0 3 2 4 0
3. 5 . 0 3 3 0 0
4. 5 . 0 3 4 2 0
6 . 3 3 k 0 . 0 1 8.3?0*, 1
6 . 0 0 1 1 . 0
4 .85
4 . 8 6
4.0
11.0
5 . 2 . 1 2 3 0 0 1 . 7 7 7.0
Some deconipos i t ion o f t h e t o t a l complex o c c u r s u s i n g O Z O ~ C ~!y;der ;i~',
a c i d i c c o n d i t i o n w i t h a s t e e l w o o l c a t a l y s t . T h e r e a c t i o n k-.s
t h e complex c e a s e d . F o r p H < 3 . 0 , t h e complex i s o x i d i z e d t o ;Ton i lydroxide and c y a n a t e . The i r o n r e a c t s immedia te ly w i t h f r e e complex c y a n i d e t o form e i t h e r f e r r o u s f e r r o c y a n i d e o r f e r r l c f e r r o c y a n i d e . The r e a c t i o n c o n t i n u e s t o follow t h i s p a t h u n : i l no f r e e s o l u b l e complex c y a n i d e r e m a i n s .
I I
I I very s e n s i t i v e t o changes i n p l i . For p H > 3 . 0 , d e c o m p o s i t i o n c f
Hot a c i d i c o z o n a t i o n s were pe r fo rmed i n a t e m p e r a t u r e r a n g e o f 7 0 " - 9 0 ° C w i t h o u t t h e u s e of c a t a l y s t s . The pH was h e l d below 1 . 5 . F i g u r e s 2 2 (page 7 2 ) and 2 3 (page 73 ) show t h e resu1:s of t h o s e s t u d i e s . F i g u r e 2 2 shows t h e e f f e c t o f o z o n a t i o n t ime on t o t a l c o n c e n t r a t i o n of complex c y a n i d e ; i n c l u d i n g any r e - d i s s o l v e d p r e c i p i t a t e . a i r a l o n e i s a l s o shown. I n i t i a l l y , ozone o f f e r s no i n c r e a s e i n t h e d e s t r u c t i o n o f t h e complex o v e r s i m p l y h e a t i n g and a e r a t i n g under a c i d i c c o n d i t i o n s . However, a s t h e r e a c t i o n p r o c e e d s , o z o n a t i o n promotes a more comple t e d e s t r u c t i o n o f t h e complex.
F i g u r e 23 shows t h e r e l a t i o n s h i p be tween t h e c o n c e n t r a t i o n of
ozone f e e d r a t e . From F i g u r e s 2 2 and 23 , i t was c o n c l u d e d tl-.at t h e complex p r e c i p i t a t e s from s o l u t i o n f a s t e r t h a n i t decomposes.
The i r o n f e r r o c y a n i d e p r e c i p i t a t e s t a r t e d w i t h i t s c h a r a c t e r i s - t i c b l u e c o l o r b u t , as t h e r e a c t i o n p r o c e e d e d , i t t u r n e d t o a b l a c k g r a n u l a r p r e c i p i t a t e t h a t s e t t l e d r a p i d l y . The t r a n s i t i o n was g e n e r a l l y comple t e when t h e t o t a l c o n c e n t r a t i o n o f complex had been r educed t o t w o - t h i r d s o f t h e o r i g i n a l c o n c e n t r a t i o n . The p r e c i p i t a t e d i d n o t e x h i b i t c h a r a c t e r i s t i c s o f common i r o n f e r r o c y a n i d e m i x t u r e s . I t d i s s o l v e d o n l y above pH 1 3 . 0 . C o z - p l e x c y a n i d e s c o u l d b e e x t r a c t e d from t h e p r e c i p i t a t e w i t h con- c e n t r a t e d ammonium h y d r o x i d e w i t h o u t chang ing t h e p h y s i c a l appea rance o f t h e p r e c i p i t a t e . Ammonia was q u a l i t a t i v e l y i d e n - t i f i e d as one o f t h e d e c o m p o s i t i o n p r o d u c t s . The f o r m a t i o n o f ammonia i s p r o b a b l y due t o - a " r e v e r s i o n " r e a c t i o n o f f e r r i c y a n i d e t o f e r r o c y a n i d e :
Hot a c i d i c t r e a t m e n t of t h e complex w i t h
s o l u b l e complex ( i n s o l u t i o n ) and o z o n a t i o n t ime a t a c o n s t a n t
4 Fe(CN)6'3 + 6 OH- + 3 H20 + 02+ 2 Fe(CN)6 - 4 + 2 Fe O'H20 +
2 NH + 2 C 0 2 + 10 C N - ( 4 5 ) 3
A f low scheme f o r a f e r r o c y a n i d e decompos i t ion u n i t i s shown i n F i g u r e 2 4 (page 7 4 ) . The w a s t e f e r r o c y a n i d e and h y d r o c h l o r i c a c i d a r e i n j e c t e d i n t o t h e r e a c t o r v e s s e l where t h e y a re h e a t e d and o z o n a t e d . The o v e r f l o w from t h e r e a c t o r i s t h e n f i l t e r e d t o remove t h e p r e c i p i t a t e t h a t i s formed d u r i n g t h e decompos i t ion . The s o l u t i o n l e a v i n g t h e f i l t e r i s n e u t r a l i z e d w i t h sodium hydrox ide and sewered . The p r e c i p i t a t e from t h e f i l t e r i s c o l - l e c t e d and t r e a t e d w i t h sodium h y d r o x i d e s o l u t i o n t o e x t r a c t t h e complex c y a n i d e s , T h i s s l u r r y i s t h e n f i l t e r e d and t h e f i l t r a t e i s r e c i r c u l a t e d i n t o t h e r e a c t o r . The f i n a l p r o d u c t s a r e sodium c h l o r i d e and i r o n h y d r o z i d e t o t a l i n g a b o u t s i x pounds p e r da?. f o r t h e "average" p r o c e s s i n g inachine.
7 1
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VI
2003 0' r
c,
I+ 0.002
I ! I j !
! I I
+
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l
0 0 20 9 40 50 60 70 80 90 100 110 120 Time (Min)
Figure 22 Rate of Degradation of Total F e ( C N ) 6 During Acid
Ozone Oxidation Between 70" - 90°C
72
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C o s t / \ i i a l \ * s i s f o r Oionc 1)cconlposit i o n o r Complcx C y n r l i d c s
l - 1 1 ~ c o s t a n a l y s i s f o r . t h c d e s t r u c t i o n ol: €crrocyanidc u s i n g 0:onc i s 3 g a i n bascd on t h c ' ' a v c r a g c ' ' p r o c e s s i n g machinc (pagc 37). Thc runl . r ing t i n e f o r t h e machine was s c t a t c i g l l t h o u r s p c r d a y . ~ q u i p ~ c n t s i z e was b a s e d on a t w c n t y - i o u r h o u r d e s t r u c t i o n c y c l c . The equipllrcnt c o s t es t imate f o r t h i s u n i t i S l i s t e d be low: (25)
4
E q u i pme n t
R e a c t o r vessel; glass-lined steel, SO g a l '
N i x i n g t a n k s ; p o l y e s t e r 50 g a l
P o r t a b l e m i x e r s ; 2 hp r u b b e r c o a t e d s t e e l
H e a t i n g c o i l ; DuPont T e f l o n immers ion c o i l
Pumps; c o r r o s i o n r e s i s t a n t
F i l t e r p r e s s e s ; p l a t e a n d frame
Ozone g e n e r a t i o n u n i t (200 gm/hr)
Labor and m a i n t e n a n c e ( e s t i m a t e d a t 19% cos t !
T o t a l
D a i l y Chemica l Cos t s Q u a n t i t y 1) Oxygen 200 c u b i c f t
C o s t / U n i t
$ 2,000
$ 200
$ 550
$ 1,000
$ 250
$ 1,200
$ 1 4 , 0 0 0
$ 2,480
$25 ,680
c o s t
$ 6 . 6 0
- 2) H y d r o c h l o r i c a c i d 1 l i t e r $ . 7 5
3) Sodium h y d r o x i d e 1 pound $ ,30
D a i l y C o s t of D e s t r u c t i o n : 1 0 y e a r s ) . I n c r e a s e i n , c o s t of p r o c e s s i n g per r o l l of film: Z+/ ro l l .
$171.5'0 ( e q u i p m e n t a m o r t i z e d o v e r
I 7 5 . . .
Removal o f Heavy Complex Cyanides
' I i ' :/Ii I j
!t' P r e c i p i t a t i o n
(Subprogram D)
Copper and z i n c were t h e b e s t m e t a l s t e s t e d w i t h r e g a r d t o comple t eness o f heavy m e t a l f e r r o c y a n i d e p r e c i p i t a t i o n . e v e r , t h e d i f f e r e n c e be tween t h e v a r i o u s m e t a l s t e s t e d was small . T a b l e VI11 (page 7 7 ) shows t h a t t h e b e s t f e r r o c y a n i d e removal r e s u l t e d u s i n g z i n c i o n , ( 9 9 . 8 % ) w h i l e t h e l e a s t e f f e c t i v e was i r o n ( 9 9 . 4 % ) . Copper and z i n c p r e c i p i t a t e s were t h e s l o w e s t t o s e t t l e . A f t e r t h i r t y m i n u t e s , t h e z i n c p r e c i p i t a t e had s e t t l e d t o o n l y 4 0 % o f t h e o r i g i n a l s o l u t i o n h e i g h t , page 7 7 ) . R e s u l t s o f v a r y i n g pH showed a somewhat lower f e r r o c y a n i d e c o n - c e n t r a t i o n when s t a r t i n g w i t h a l k a l i n e s o l u t i o n s . i o n , beyond t h e s t o i c h i o m e t r i c amount f o r comple t e p r e c i p i t a t i o n , l owered t h e f e r r o c y a n i d e c o n c e n t r a t i o n i n t h e s u p e r n a t a n t o n l y
c e n t r a t i o n t o 2 5 % o f t h a t r ema in ing when t h e s t o i c h i o m e t r i c amount of metal was u s e d , A d d i t i o n a l e x c e s s d i d n o t lower t h e concen- t r a t i o n f u r t h e r . (See T a b l e X , page 7 8 ) .
How-
(See T a b l e IX
Excess m e t a l
* w i t h c o p p e r and z i n c . 1 0 % e x c e s s m e t a l r educed t h e complex con-
S e v e r a l t e s t s w e r e r u n w i t h f e r r i c y a n i d e and combina t ions o f i f e r r o - a n d f e r r i c y a n i d e . These e x p e r i m e n t s i n d i c a t e d t h a t f e r r i - c y a n i d e w i l l n o t p r e c i p i t a t e w e l l by i t s e l f . A 9 0 e r c e n t r e -
I d u c t i o n of p u r e f e r r i c y a n i d e was o b t a i n e d u s i n g Fe+q a s t h e p r e - c i p i t a n t , w h i l e t h e o t h e r m e t a l s o n l y removed a b o u t 6 0 % o f t h e Fe(CN) s o l u t i g n , r e d u c t i o n s $ 5 9 9 . 5 9 o r bet: r i n b o t h complex
, Cd+2 and Cu '. (See T a b l e s XI-XIII).
The a n a l y t i c a l p r o c e d u r e f o r f e r r o - a n d f e r r i c y a n i d e i n t h i s s e c t i o n c a l l e d f o r f i l t e r i n g each sample t h r o u g h Whatman 2V f i l t e r p a p e r a s t h e f i r s t s t e p . p a p e r and i t s a b s o r b a n c e measured a g a i n s t t h e same w a t e r which had n o t been f i l t e r e d , t h e v a l u e s a t 2 2 0 mu ranged f r o m 0 . 0 8 t o 0 . 3 5 . T h i s would c o r r e s p o n d t o a f e r r o c y a n i d e c o n c e n t r a t i o n o f f rom 0 . 9 t o 4 . 0 m g / l i t e r . The w a t e r was a p p a r e n t l y l e a c h i n g a m a t e r i a l f r o m t h e p a p e r which c o n t r i b u t e d t o t h e abso rbance a t 2 2 0 mu. I f t h e water was made a c i d , i t had a h i g h e r a b s o r b a n c e a f t e r f i l t r a t i o n t h a n a n e u t r a l s a m p l e , and t y p e s of f i l t e r p a p e r were t r i e d ; a l l w i t h a b o u t t h e same r e s u l t s . The re d i d n o t seem t o b e a u s e f u l c o r r e c t i o n f a c t o r b e c a u s e o f t h e wide d a i l y v a r i a t i o n s . f e r r o c y a n i d e c o n c e n t r a t i o n s may b e h i g h e r t h a n t h e a c t u a l concen- t r a t i o n .
However, w i t h b o t h f e r r o - a n d f e r r i c y a n i d e i n t h e c y a n i d e s
' were o b t a i n e d w i t h Fe
When d i s t i l l e d w a t e r was r u n t h r o u g h t h i s
S e v e r a l d i f f e r e n t b r a n d s
As a r e s u l t , t h e o b s e r v e d
7 6
111,
:0 !d
L - :a1 .on,
In- iount 1-
des
ction er
0 f
e nds
e d en-
TABLE V I 1 1
EFFECT OF XNITlAL pli ON FERROCYANIDE
(Fe (CN) G - ~ ) CONCENTKATION
( m g / l after 30 min settling)
e
(Initial Conc. 750 m g / l Total Complex Cyanide in Each Solution)
TABLE IX
EFFECT OF INITIAL pH ON HEAVY METAL
FERROCYANIDE PRECIPITATION RATE
( % of initial solution height after 30 min settling)
Fe
2 2
29
16
19
Mn
8
4
10
12
L
Cd _I
11
8
10
15 A 4
Cu
34
34
30
28
L Zn
38
46
40
35
-
7 7
TABLE X
EFFECT OF EXCESS HEAVY METAL ON
FERROCYANIDE (Fe (CN) 6-4) SOLUTION CONCENTRATION (mg/l after 30 min settling)
* 1 2 5 * l o o ble tal
* 2 0 0 I on
Fe 6.7 2.9 2 . 8 3 . 1 4 . 1
bin 4 . 2 2 .6 3 . 0 3.0 3 .5
Cd 2 .4 2 . 9 2 .5 3 . 1 2 .7
cu 2 .4 4 .5 1 . 3 1 . 3 1.4
Zn 0 . 7 2 . 3 0.6 0 . 7 0.6
- - *110 - - * 9 0 - -
* PERCENT STOICHIOMETRIC SALT SOLUTION ?Initial Conc. 7 5 0 mg/l Total Complex Cyanide in Each Solution)
bletal I on
TABLE XI
EFFECT OF TEMPERATURE ON HEAVY METAL
FERROCYANIDE (Fe (CN) 6 ) CONCENTRATION
(mg/l after 30 min settling)
-4
- 26°C 46°C - Fe 6.0 4 .0
Mn
Cd
cu
3.6
2 . 3
4.1
3.0
4.0
5 . 0
56°C
4 . 4
1.8
1 .3
4.1
Zn 0.9 3.0 2 . 5
(Initial Conc. 7 5 0 mg/l Total Complex Cyanide in Each Solution)
78
TABLE XI1 A
HLiIVY hIETi\I, 1’RI’CII~~’~ATI~N OF COMPLEX CYANIDES FROM
SOLUTIONS (-(’‘;! \ I ‘ I h l l l \d’rI[ FEKRO-.4ND FERRICYANIDE SALTS
(Initial C O I ~ L . i > O , ~ g / l T o t a l Complex Cyanide in Each Solution)
( m g / l ferrocyanide after 30 min settling)
* s o - * 7 5. - * 9 0 ble tal I on
En 2.9 3.0 2 . 3
* l o o - * 9 5 - - - 2.0 2.6 3 . 3 0
A -
Nn
Cd
- - -
2 . 6
2 . 9
2 . 7 4 . 2
2 .2 2 . 4
7 .0 1 2 . 8
2 .0 2 .2
_ - A l u . z 13.4 U 5 . 2 4.0 3 . 6 CU 4.5
Zn 2 . 3 4 . 2 5 . 9 4 .8 10.2 4.1 0
*PERCENT FERROCYANIDE IN SOLUTION
TABLE XI1 B
HEAVY METAL PRECIPITATION OF COMPLEX CYANIULS PKUM
SOLUTIONS CONTAINING BOTH FERRO-AND FERRICYANIDE SALTS I
I
(Initial Conc. 750 mg/l Total Complex Cyanide in Each Solution)
(mg/l ferricyanide after 30 min s’ettling)
Metal Ion * l o o - * 50 - * 7 5 - * 2 5 *lO -
1.0 1.1 1.0 7 4 1 . 2 0 . 5 Fe
5 3 1 6 1 0 . 2 0 Mn 3 0 0 190 1 8 4
3 . 2 5 . 2 2 .5 0
0 . 8 4.0 3 . 8 0
Cd 3 2 7 2 .8 5 .0
3 0 7 5 .7 7 .0 cu
45 46 2 4 0 2 5 6 4 7 5 5 Zn
*PERCENT FERRICYANIDE IN SO1
79
,UTION
TABLE XI11 A
EFFECT'OF SETTLING TIME ON
FERROCYANIDE CONCENTRATION
"1 Fe (CN) 6 - 4 1
30 Min 5 Min 1 0 Min 20 Min - Me t a l I on
Fe
hln
Cd
cu
Zn
- - - 2.9 3 . 1 3 . 5 3 . 1
6 . 8 6 . 2 6 . 1 5 .9
1 . 9 2.0 2 . 2 2 . 2
3 , 8 5.9
3 . 9 4 . 1
4 . 1 ' 4 .2
4 . 3 4 . 1
'(Initial Conc. 750 mg/l Total Complex Cyanide in Each Solution)
TABLE XI11 B
EFFECT OF SETTLING TIME ON
FERRICYANIDE CONCENTRATION
' 1 Metal 20 Min 30 Min 10 Min
64
2 5 7 272
Ion 5 Min - Fe 7 4 - B i
P 6 4 6 8
2 5 1 2 5 1 Mn
Cd
cu
Zn
330 435 4 1 0 39 7
3 2 0 3 1 5
267 26 7
360 30 2
2 5 2 246
r i i i I
~
I
i
, I
80
b)
F o r t h e p u r p o s e o f compar ison i n t h e c e n t r i f u g a t i o n s t u d i e s , c l a r i t y o f c e n t r i f u g e e f f l u e n t was d e f i n e d a s t h e i n v e r s e o f a b s o r b a n c e . As an example , i f a sample had an a b s o r b a n c e o f 0 . 5 0 , i t s c l a r i t y was 2 . 0 (l/O.S). Any s o l u t i o n w i t h a c l a r i t y g r e a t e r t h a n 3 .0 ( a b s o r b a n c e l e s s t h a n 0 . 3 3 ) a p p e a r e d c l ea r t o t h e u n a i d e d e y e .
I t was e x p e c t e d t h a t i n c r e a s e d r o t o r speed would p roduce g r e a t e r e f f l u e n t c l a r i t y , b u t t h a t was o n l y p a r t i a l l y c o n f i r m e d . As r o t o r s p e e d was i n c r e a s e d , t h e c l a r i t y "peaked" ( i e . , i n c r e a s e d t h e n d e c r e a s e d ) . The S o r v a l l c e n t r i f u g e u s e d i n t h e s t u d y p roduced v e r y l a r g e " g " f o r c e s ; up t o 30,000 t i m e s t h e f o r c e o f g r a v i t y . T h i s c e n t r i p e t a l f o r c e may have b e e n enough t o b r e a k up t h e r a t h e r l o o s e l y bonded a g g r e g a t e p a r t i c l e s , h e l d t o g e t h e r by t h e f l o c c u - l a n t .
4 I t was a l s o a n t i c i p t a t e d t h a t d e c r e a s i n g t h e s l u r r y f low r a t e t h r o u g h t h e c e n t r i f u g e ( i n c r e a s i n g t h e r e s i d e n c e t i m e ) would i n c r e a s e c l a r i t y . Aga in , t h i s was found t o b e o n l y p a r t l y t r u e w i t h t h i s s y s t e m d e s i g n . i n t o t h e c o l l e c t i o n t u b e s and e x p e l l e d w i t h t h e e f f l u e n t . While i n s i d e t h e t u b e s , t h e a i r b u b b l e s d i s t u r b e d t h e s e t t l i n g p a r t i - c l e s and o f f s e t t h e b e n e f i t s o f t h e l o n g e r r e s i d e n c e t ime. C l a r - i t y , t h e n f i r s t i n c r e a s e d a s t h e f l o w r a t e d e c r e a s e d f o r t h i s p a r t i c u l a r s y s t e m .
A d d i t i o n o f N a l c o l y t e 6 7 0 o r P u r i f l o c A-23 p roduced v i s i b l y l a r g e r p r e c i p i t a t e p a r t i c l e s . lier re c l a r i t y was a maximum u n d e r t h e c o n d i t i o n s o f v a r i a b l e f l o w r a t e o r r o t o r s p e e d . T h a t i s , t h e a d d i t i o n of i n c r e a s i n g amounts o f f l o c c u l a n t p roduced c l a r i t y "peak" p o i n t s a t p r o - g r e s s i v e l y lower rpm ' s i n t h e r o t o r s t u d y and a t p r o g r e s s i v e l y h i g h e r f l o w r a t e s i n t h e f l o w s t u d y . The f l o c c u l a n t a l s o iri- c r e a s e d t h e amount of m a t e r i a l removed f rom s o l u t i o n a t t h e s e "peak" p o i n t s . For e ample, F i g u r e 2 5 (page 8 3 ) shows a r o t o r s p e e d s t u d y u s i n g Fe+' i o n . peak i s 5 . 0 a t 8200 rpm f o r t h e r o t o r s t u d y and 50 ml/min f o r t h e f low s t u d y .
P u r i f l o c A-23 p roduced g e n e r a l l y g r e a t e r c l a r i t y t h a n N a l c o l y t e 6 7 0 a t t h e same c o n c e n t r a t i o n . N a l c o l y t e p roduced l a r g e g e l a t i n o u s p a r t i c l e s which c a u s e d c l o g g i n g o f t h e i n l e t p o r t s . The s e d i m e n t b u i l d - u p i n t h e c o l - l e c t i o n t u b e s was q u i t e r a p i d and r e q u i r e d f r e q u e n t c l e a n i n g o f t h e sys t em.
A l l of t h e m e t a l i o n s s t u d i e d p roduced s l u r r i e s t h a t would cen - t r i f u g e w e l l enough, unde r optimum c o n d i t i o n s , t o g i v e e f f l u e n t s c l e a r t o t h e u n a i d e d e y e w i t h o u t t h e u s e o f f i 2 c c u l a n t s Under o p t i m i z e d r o t o r s p e e d and f l o w r a t e , Zn+2, Cd w i t h e i t h e r f l o c c u l a n S p roduced e f f l u e n t s which showed a b s o r b - a n c e s c o r r e s p o n d i n g t o less t h a n 1 m g / l i t e r complex c y a n i d e .
A t low r a t e s , a i r was p r o b a b l y t a k e n
T h i s a d d i t i o n changed t h e p o i n t s
Wi thou t f l o c c u l a n t , t h e c l a r i t y
A t c o n c e n t r a t i o n s of 5 gpm,
and Mn+2 s l u r r i e s ,
i ' i ; i : I
I
8 3
Figures 25 -34 show the results o f the r o t o r s p e e d and slurry f l o w studies on the centrifuge f o r each metal and flocculant investigated.
j !
0 u c CQ P k
‘ 0 lA P < c 0
.I4 c, 3 4 0 v)
k 0
x c,
W
R o t o r Speed (rpm)
F i g u r e 25 E f f e c t o f R o t o r Speed on S o l u t i o n C l a r i t y For I r o n
P r e c i p i t a t i o n of Complex Cyanide Using V a r i o u s F l o c c u l a n t s
a 3
if
Figure 26 Effect of Rotor Speed on Solution Clarity f o r
Manganese Precipitation of Complex Cyanide Using Various Flocculants
a 4
F i g u r e 2 7
P r e c i p i t a t i o n o f Complex Cyanide Using Various F l o c c u l a n t s
E f f e c t o f R o t o r Speed on S o l u t i o n C l a r i t y For Cadmium
8 5
Rotor Speed (rpm)
Figure 28 Effect of R o t o r Speed on Solution Clarity for Copper -
Precipitation of Complex Cyanide Using Various Flocculants
86
A
IO 8 6 4 2 0 10 8 6 4 2 0 10 8 6 4 2 0 IO 8 6 4 2 0 10
6 4 2
a
1 I I I I I I I 1 I 1 I
0 0
LQ
0 0
- a, v. a, N, g 8 " " " O 0 0 0 0 0 0 8 0 0
4 - " m, w, 0, -4-8 a, 7 9 0 1
0 0 0 0
- N e m - ( D o o m - I - - - - ;E Roto r Speed (rpm) J
$
Figure 29 Effect of Roto r Speed on Solution C l a r i t y for Zinc.
Precipitation of Complex Cyanide Using Various Flocculants
8 7
-
F l o w Rat:
F i g u r e 30 E f f e c t o f F low Ra te
P r e c i p i t a t i o n o f Complex Cyanii
on S o l u t i o n C l a r i t y f o r Iron
e Using Various Flocculants
8 8
F l o w Rate (ml/min)
Figure :sl
Precipitation of Complex Cyanides Using Various Flocculants
i . i ! L L t 0 1 - i ' low Rate on Solution Clarity for Manganese
89
Flow Rate (ml/min)
Figure 32
Precipitation of Complex Cyanides Using Various Flocculants
Effect of Flow Rate on Solution Clarity for Cadmium
9 0
6 4 2 0 10 8 6 4
1
I
F l o w Rate (ml/min)
Figure 33
Precipitation of Complex Cyanides Using Various Flocculants
Effect of Flow Rate on S o l u t i o n Clarity for Copper
91
F l o w Rate (ml/min)
Figure 34 E f f e c t of F l o w R a t e on S o l u t i o n C l a r i t y f o r Zinc
Precipitation of Complex Cyanides Using V a r i o u s Flocculants
92
I I
J
h
i 0 t
C h l o r i n e D e s t r u c t i o n o f Complex Cyanides
(Subprogram E)
Some d i f f i c u l t y was e n c o u n t e r e d i n c h l o r i n a t i o n s t u d i e s l o n g e r t h a n 20 to 25 h o u r s i n d u r a t i o n due t o s o l u t i o n s a t u r a t i o n o f v a r i o u s s a l t s . These i n c l u d e d sodium c h l o r i d e , p o t a s s i u m c h l o r i d e and sodium h y p o c h l o r i t e . The s a l t s had t o b e removed by f i l - t r a t i o n . I n a d d i t i o n , a s a t i s f a c t o r y u n s o p h i s t i c a t e d method o f pH c o n t r o l f o r l ong t e rm s t u d i e s was n o t f o u n d .
I n g e n e r a l , complex c y a n i d e d e s t r u c t i o n by a l k a l i n e c h l o r i n a t i o n a t room t e m p e r a t u r e was found t o b e v e r y s low ( F i g u r e 35 , page 9 4 ) . On t h e b a s i s o f a one week t e s t , i t would r e q u i r e t h r e e weeks f o r 5 0 0 m l s o f Chlorox t o d e s t r o y t h e f e r r i c y a n i d e i n 5 0 0 ml o f a 20 g / l i t e r p o t a s s i u m f e r r i c y a n i d e {K3Fe(CN) } s o l u t i o n a t 20OC. A t 6 0 ° C t h e same amount c o u l d b e decomposed i$ l e s s t h a n t h r e e
* d a y s , w h i l e a t 9 0 ° C t h e d e c o m p o s i t i o n would o n l y t a k e a b o u t f o u r h o u r s ( F i g u r e 3 6 , page 9 5 ) .
None of t h e c a t a l y s t s (AgNO , NaN03, CdS04, s t e e l wool) a p p e a r e d
ambient t e m p e r a t u r e . The me ta l i o n s (Ag', Cd , Cu ) p r e c i p i t a t e d a s heavy metal s a l t s o f t h e i r o n c y a n i d e complexes . The s t e e l woo l showed no e f f e c t i n n e u t r a l o r b a s i c s o l u t i o n s , however , i n s t r o n g a c i d s o l u t i o n s i t d i s s o l v e d and p r e c i p i t a t e d as f e r r o u s f e r r i c y a n i d e . No f r e e c y a n i d e , hydrogen c y a n i d e o r c y a n a t e were found i n t h e c h l o r i n a t e d s o l u t i o n o r i n t h e decompos i t ion p r o d u c t s . The n l y p r o d u c t s d e f i n i t e l y i d e n t i f i e d were ammonia and f e r r i c ( F e f g ) i o n .
t o i n c r e a s e t h e r a t e o f des 2 r u c t i o n o f t h e c o y p l e x Eyanide a t
A l k a l i n e and a c i d c h l o r i n a t i o n o f f e r r i c y a n i d e a p p a r e n t l y p r o - c e e d by d i f f e r e n t mechanisms. When c h l o r i n e was bubb led i n t o an a l k a l i n e s o l u t i o n , t h e s o l u t i o n d a r k e n e d s l i g h t l y and i r o n h y d r o x i d e , F e ( O H ) 3 , p r e c i p i t a t e d . t h e p r e s e n c e of c y a n a t e and t h e r e a c t i o n p r o c e e d e d t o comple t ion .
I n a c i d m e d i a , t h e s o l u t i o n t u r n e d r e d , t h e n d a r k e n e d t o g r e e n - b l a c k . As t h e r e a c t i o n p r o c e e d e d , a g r a n u l a r , g r e e n - b l a c k p r e - c i p i t a t e formed and c y a n a t e was n o t o b s e r v e d . The maximum a t t a i n a b l e d e c o m p o s i t i o n w i t h a c i d c h l o r i n a t i o n was 8 5 % ; t h e o t h e r 1 5 % o f t h e f e r r i c y a n i d e complex r e m a i n i n g i n t h e p r e c i p - i t a t e . However, i f t h e s o l u t i o n was b a s i f i e d and t h e r e s u l t i n g p r e c i p i t a t e removed, c h l o r i n a t i o n of t h e f i l t r a t e wou ld b e r e - p e a t e d and a n a d d i t i o n a l 8 5 % o f t h e complex removed. T h i s p r o - c e s s o f r e c y c l i n g t h e p r e c i p i t a t e w i t h a c i d c h l o r i n a t i o n t o t h e d e s i r e d f e r r i c y a n i d e l e v e l a p p e a r s t o be t h e most successful '
d e s t r u c t i o n p r o c e d u r e u s i n g c h l o r i n e ;
Q u a l i t a t i v e t e s t s showed
9 3
p
I
C h l o r i n a t i o n D e s t r u c t i o n Cos t A n a l y s i s
D c s i r u c t i o n o f f e r r i c y a n i d e c a n be a c h i e v e d under a c i d i c o r a l k a l i n e c o n d i t i o n s . E i t h e r method would r e a u i r e a p p r o x i m a t e l y t h e saine equipment and each p roduce f e r r i c h y d r o x i d c ^ a s an end' p r o d u c t a t t h e r a t e o f a b o u t f o u r pounds p e r day f o r t h e "com- b i n e d ave rage" p r o c e s s o r , F e r r i c h y d r o x i d e i s n o t a r e a d i l y s a l e a b l e p r o d u c t .
Acid C h l o r i n a t i o n (Figure 3 7 , Page 9 9 )
For a c i d c h l o r i n a t i o n d e s t r u c t i o n of complex c y a n i d e s , t h e b l e a c h o v e r f l o w i s f i r s t c o l l e c t e d and h e a t e d t o a b o u t 90°C. C h l o r i n e gas i s pumped i n t o t h e s o l u t i o n and a l l o w e d t o p roduce an a c i d media , When t h e maximum d e c o m p o s i t i o n has been r e a c h e d ( 8 5 % ) , N a O H i s added t o p r e c i p i t a t e t h e i r o n . The r e s u l t i n g s l u r r y i s pumped t h r o u g h a f i l t e r p r e s s and t h e f i l t r a t e r e t u r n e d f o r f u r t h e r c h l o r i n a t i o n .
The "Cornbined Average" p r o c e s s o r r e q u i r e s 5 . 1 5 kg o f sodium f e r r i c y a n i d e t o p r o c e s s 800 r o l l s o f p h o t o g r a p h i c m a t e r i a l s .
Acid C h l o r i n a t i o n
Equipment
R e a c t o r V e s s e l ; g l a s s - l i n e d s t e e l , 50 g a l
P o r t a b l e M i x e r s , 2 hp r u b b e r c o a t e d s t e e l
H e a t i n g C o i l : DuPont t e f l o n immersion c o i l
Pumps; C o r r o s i o n r e s i s t a n t
F i l t e r P r e s s e s ; p l a t e and frame
Labor and m a i n t e n a n c e ( e s t i m a t e d a t 2 0 % c o s t )
C o s t / U n i t
$ 2.J 0 0 0
$ 5 5 0
$ 1 , 0 0 0
$ 250
$ 1 , 2 0 0
$1,000 w
$ 6 , 0 0 0
Q 6
Chlorine Gas
Daily Chemical Costs
1 7 6 ft3 $8.00
Sodium Hydroxide 20 lbs. $5.50
Hydrochloric Acid 1 liter $0.50
Daily Cost of Destruction: $16.25 [equipment amortized over
Increase in Cost of Processing per roll of film: 2+/roll 10 yearsj
Alkaline Chlorination (Figure 37, page 99 )
Ferricyanide waste bleach overflow would be collected a n d heated to 90°C. During continuous applied chlorination, NaOH is added to maintain alkaline conditions. When the reaction is complete, the solution is pumped through a filter press and the ferric hydroxide removed and dumped, The filtrate is neutralized with HC1 and sewered.
Alkaline Chlorination
Equipment
Reactor Vessel; glass-lined steel, 5 0 gal
Portable Mixers, 2 hp rubber coated steel
Heating Coil: DuPont teflon immersion coil
Pumps; Corrosion resistant
, Filter Presses; plate and frame
Labor and Maintenance (estimated at 20% cost)
Cos t/Uni t
$ 2 , 0 0 0
$ 5 5 0
$1,000
$ 2 5 0
$ 1 , 2 0 0
$1,000
$6,000
9 7
Chlorine Gas
Quantity
710 ft3
c o s t
$ 3 0 . 0 0
Sodium Hydroxide
Hydrochloric Acid
80 l b s
4 liters
$ 2 5 . 0 0
$ 2 . 0 0
D a i l y Cost of Destruction: $59.25 [equipment amortized over
Increase in C o s t of Processing per roll of film: 7.54/roll 10 years]
I
i
Coil
Sewer
Alkaline Chlorination:
Bleach Overflow
NaOH 7Ly HC1
Filter Press c y A v To
t n.- w- . Heating Coil
Figure 37 Chlorination System : Flow Schematics
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SECTION V I I
F U L L SCALE O Z O N E BLEACH REGENERATION
A X D WSTE DESTRUC~ION I N S T A L L A T I O W - B E R K E Y PHOTO
O z o n e G e n e r a t i o n and D i s t r i b u t i o n System
The f low d iag ram o f t h e b l e a c h r e g e n e r a t i o n s y s t e m and t h e con- c e n t r a t e d w a s t e o x i d a t i o n s y s t e m i s shown i n F i g u r e 37A (page 1 0 0 ) . The main u n i t s of t h e i n s t a l l a t i o n a r e shown i n Figure 38 (page 1 0 2 ) . The two u n i t s were m a n u f a c t u r e d unde r t h e t r adename OzPAC by Computer ized P o l l u t i o n Abatement C o r p . , L e i c e s t e r , N . Y . The u n i t on t h e r i g h t i s a 1 0 0 gm/hr ozone u n i t , u s e d f o r t h e t r r a t n e n t of w a s t e p h o t o g r a p h i c s o l u t i o n s t o r e d u c e t h e c h l o r i n e demand. The u n i t on t h e l e f t i s a 6 0 gm/hr ozone u n i t , u s e d f o r b l e a c h r e g e n - e r a t i o n and w a s t e t r e a t m e n t .
1 0 0 gm/hour U n i t
T h i s u n i t d i s t r i b u t e s ozone t o t h r e e d i f f e r e n t w a s t e t r e a t m e n t t a n k s by means o f t h r e e f l o w r e g u l a t o r s . These r e g u l a t o r s a r e
‘mounted on t h e f r o n t p a n e l (uppe r l e f t ) o f t h e u n i t . The uppe r r i g h t hand f r o n t p a n e l c o n t a i n s a pH t r a n s m i t t e r and r e c o r d e r . These u n i t s c o n s t a n t l y m o n i t o r t h e pH o f t h e waste e f f l u e n t p r i o r t o s e w e r i n g .
6 0 gm/hour U n i t
T h i s u n i t s e r v e s a d u a l f u n c t i o n , I t s p r i m a r y u s e i s f o r b l e a c h r e g e n e r a t i o n , w i t h s e c o n d a r y u s e f o r w a s t e t r e a t m e n t . When used f o r b l e a c h r e g e n e r a t i o n , t h e ozone i s p i p e d t o t h e t a n k s immedi- a t e l y b e h i n d t h e u n i t . t h e pH t r a n s m i t t e r (mounted on t h e u p p e r r i g h t f r o n t p a n e l ) and i s a u t o m a t i c a l l y m a i n t a i n e d a t t h e d e s i r e d l e v e l by t h e a d d i t i o n o f H B r .
The pH of t h e b l e a c h i s c o n t r o l l e d by
B leach R e g e n e r a t i o n Tanks
F i g u r e 39 (page 1 0 3 ) shows t h e two t a n k s u s e d i n b l e a c h r e g e n - e r a t i o n . The s p e n t b l e a c h flows, by g r a v i t y , i n t o t h e t a n k a t t h e l e f t , f r o m t h e p h o t o g r a p h i c p r o c e s s o r s on t h e f l o o r above. F o r r e g e n e r a t i o n , t h e d e s i r e d amount of s p e n t b l e a c h i s t h e n pumped t o t h e t a n k on t h e r i g h t . A f t e r t e s t i n g f o r t h e concen- t r a t i o n s o f f e r r o - a n d f e r r i c y a n i d e p r e s e n t , t h e p r o p e r amount o f ozone i s f e d i n t o t h e b l e a c h , The r e g e n e r a t e d b l e a c h i s t h e n pumped u p s t a i r s t o a mix ing room, where a small amount o f s o l i d f e r r i c y a n i d e i s added. The b l e a c h i s f i n a l l y pumped t o the re- p l e n i s h m e n t t a n k f o r r e u s e .
1 0 1
i I
I I
i I
i
Figure 38 Ozone Generation And Distribution Systems
Installed at Berkey Film Processing Plant,
F i tchburg , Massachusetts
i02
Figure 39 Ferricyanide Bleach Regeneration Tanks
at Berkey Film Processing P l a n t , Fitchburg,
Massachusetts
103
P h o t o g r a p h i c \Vas t e Trea tmen t Tanks
T h i s sys t em c o n s i s t s o f t h r e e t a n k s on d i f f e r e n t e l e v a t i o n s . A f t e r i n t r o d u c t i o n i n t o t h e h i g h e s t t a n k , t h e was te s o l u t i o n s t o b e t r e a t e d c a s c a d e t o t h e l o w e s t t a n k , f rom which t h e y a r e sewered .
The w a s t e s o l u t i o n s f o r t h i s s y s t e m a r e i n t r o d u c e d from t h r e e d i f f e r e n t p o i n t s , F i r s t , t h e r e i s a c o n t i n u o u s o v e r f l o w from t h e v a r i o u s p h o t o g r a p h i c p r o c e s s o r s . Second, t h e r e i s an i n t e r - m i t a n t f l o w of d e s i l v e r e d w a s t e f i x s o l u t i o n from a s e r i e s o f e l e c t r o l y t i c s i l v e r r e c o v e r y c e l l s . The l a s t s o u r c e i s a s m a l l c o n s t a n t f l o w from a s e r i e s o f f o u r w a s t e h o l d i n g t a n k s , k h i c h p r o v i d e s t o r a g e f o r l a r g e dumps, p r e v e n t i n g s l u g s o f m a t e r i a l f rom p a s s i n g t h r o u g h t h e w a s t e t r e a t m e n t t a n k s t o o r a p i d l y .
The main s o u r c e o f ozone f o r t h i s sys t em i s t h e 1 0 0 gm/hour u n i t . Examples o f t h e ozone d i s t r i b u t i o n a r e : 50 gm/hr i n t h e f i r s t t a n k , 3 0 gm/hr i n t h e s e c o n d t a n k , and 2 0 gm/hr i n t h e l a s t t a n k . When t h e 60 gm/hr u n i t i s n o t b e i n g u s e d t o r e g e n e r a t e b l e a c h , a d i f f e r e n t ozone d i s t r i b u t i o n c a n b e employed, I n t h i s s y s t e m , t h e 6 0 gm/hr i s f e d i n t o t h e f i r s t t a n k and t h e 1 0 0 gm/hr i s d i s t r i b u t e d i n t o t h e l a s t two t a n k s , a t an a p p r o x i m a t e r a t i o n of SO/SO. (FigL:rc -10, ; inge 1 0 5 )
P h o t o g r a p h i c S o l u t i o n T’cs t ing S t a t i o n
F i g u r e 4 1 , (page 1 0 6 ) shows t h e comple t e t e s t i n g s t a t i o n r e - q u i r e d f o r a t y p i c a l p h o t o p r o c e s s i n g p l a n t . T e s t s o l u t i o n s a r e k e p t on a s h e l f , above a g l a s s d r y i n g r a c k . Work a r e a s a r e l o c a t e d on e i t h e r s i d e o f a s i n k . E x t r a c h e m i c a l s and g l a s s w a r e , n e c e s s a r y f o r t e s t i n g , a r e s t o r e d i n t h e c a b i n e t s u n d e r t h e s i n k . T e s t i n g which c a n b e conduc ted a t t h i s t y p e of s t a t i o n a r e : c o n c e n t r a t i o n o f f e r r o - and f e r r i c y a n i d e , pH o f b l e a c h , c h l o r i n e demand o f waste s o l u t i o n , a n d s i l v e r c o n c e n t r a t i o n i n f i x e r s o l u t i o n .
104
Figure 40 Waste Treatment Tanks at Berkey Film
Processing Plant, Fitchburg, Massachusett
105
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SLiC"i'1ON V I i I
AC KNO \JL E 1) G M E NT S
Tiic s u p 7 o i - t sild c o o p e r a t i o n o f h l r . J o e l W e i n s t e i n , B e r k e y F i l m P r o c e s s i n g P l a n t , F i t c h b u r g , M a s s a c h u s e t t s , who made t h i s s t u d y p o s s i b l e , i s a c k n o w l e d g e d w i t h s i n c e r e t h a n k s ,
The b e n c h s c a l e a n d p i l o t p l a n t s t u d i e s , a n a l y t i c a l w o r k , a n d r e p o r t p r e p a r a t i o n were p e r f o r m e d a t C o m p u t e r i z e d P o l l u t i o n A b a t e m e n t C o r p o r a t i o n , L e i c e s t e r , New York .
We a l s o a c k n o w l e d g e t h e s u p p o r t o f t h e p r o j e c t by t h e U.S. E n v i r o n m e n t a l P r o t e c t i o n Agency a n d t h e h e l p a n d g u i d a n c e o f : Fir. W i l l i a m L a c y , Mr. G e o r g e R e y , Flr. A r t h u r H. M a l l o n , a n d Nr. Thomas D e v i n e , t h e P r o j e c t O f f i c e r .
The a d d i t i o n a l s u p p o r t o f Mr. Thomas McMahon, D i r e c t o r , D i v i s i o n of Water P o l l u t i o n C o n t r o l , t h e Commonweal th of M a s s a c h u s e t t s i s a l ' so a c k n o w l e d g e d .
SECTION IX
REFERENCES
1, Sax, N. Irving, Dangerous Properties of Industrial Materials, Rheinhold Publishing Co., New York, 196-3.
2. Burdick, EIB., and Lipschvetz,, M., "Toxicity of Ferro-and Ferricyanide Solutions to Fish, and Determination of the Cause of blortality", Trans. Ami Fish SOC., 78, 192 (1948) CA 4 4 , 10939P.
3. Ono, Sinichi and Tsuchihashi, Genichi, "Oxidation of Ferro- cyanide in Aqueous Solution by Light", Bull. Chem. SOC., Jap. 38(6), p. 1052-3, 1965, (Eng.) CA 63, 6 530.
4. Emschwiller, Guy and Legros, Jacqueline, "Photochemical Hydrolysis of Ferrocyanide", Compr. Rend. 261(6), (Group7) , p. 1535-8 (1965) (Fr.) CA 63 17632e.
Photoxidation of Aqueous Fe +2'Species", Nature, 207 (5002) p. 1190-1, (1965), CA 63, 15761a.
5. Dainton, F.S. and Airey, P.L "Primary Processes of
6. Kongiel-Chablo, Irena, "Behavior of Complex Cyanides in Natural Water with High Rate of Contamination", Roczniki Panstwaowego Zakladu Hig., 17(1), p. 95-102, 1966.
in Water Ponds", Hydrochemical Materials, Vol. 37, p. 133-43, Moscow, Russia, 1964.
Biological Systems", Report EHL (K) 70-9, USAF Environmental Health Lab, Kelly Air Force Base, Aug. 1970.
Picture Film Processing" J . SMPTE, - 79, p . 765-771 ( 1 9 7 0 ) .
Hendrickson, Thomas N.,"Pollution and the Television Film Processing Laboratory". Meeting of the National Association of Broadcasters, Chicago, Illinois, April (1972).
7. Lur'e, Yu.Yu. and Panova, V.A., "Behavior of Cyano Compounds
8. "Toxic Effects of Color Photographic processing Waste on
9. West, Lloyd E , , "Disposal o f Waste Effluent from Motion-
10. Paper to be presented at the National
11. Condensed Chemical Dictionary, 5th Edition, 1956.
12. Alletag, Gerald C., "Truth in Pollution Ahatement" Paper presented at Pure Meeting, Washington, D.C., April 6, 1971..
Glasstone, S . , Textbook of Physical Chemistry, D. Van Nostrand Co., New York, 1951.
13.
1 4 , Dobcz' , T., and Dagon, T . , "Rcgcncration of Ferrocyanide B l e n c h Using Ozone", paper presented at Society of Photo- qraphic Scientists and Engineers Convention, Chicago, Illinois, April 22 , 1971.
1 5 .
16.
17.
18.
19.
io
21.
22.
23.
24 .
25.
26.
27 .
2 8 .
29 .
Levenspiel, O., Chemical Reaction Engineering, John Wiley 4 Sons inc., New York, 1964.
American Cyanamid, The 'Chemistry. of Ferrocyanides, Beacon Press, New York, 1 9 3 3 .
Selm, R.P., "Ozone Oxidation of Aqueous Cyanide Waste Solution in Stirred Batch Reactors and Packed Towers", Advances in Chemistry Series, 21, American Chemical Society, Washington, D.C. 1959.
Laubusch, E. J., "Chlorination of Wastewater", Water and Sewage Norks, v o l . 1 0 5 , 1 9 5 8 .
Moore, W., Physical Chemistry, Prentice-Hall, Englewood Cliffs, New Jersey, 1962.
U.S. Patent 2 , 9 8 1 , 6 8 2 : Chlorination of Water Soluble Iron Cyanide Compounds Using Mercuric Chloride Catalyst.
U . S . Patent 3,101,320: Conditioning Cyanide Compounds.
Kodak Professional Handbook, Motion Picture and Education harkets Division, Eastman Kodak C o . , Rochester, New York, 1967, Procedure 1 1 0 2 - A .
Ibid., procedure llOOF
Ibid., procedure l l O l B
Ibid., procedure 1122
Dryden, C. and Furlow, R., Chemical Engineering Costs, Engineering Experiment Station, Ohio State University, Columbus, Ohio, 1966.
G . J . Alohanrao, K.P. Xeishnamoorthis and 1V.M. Deshande, "Photo-Film Industry Waste: Pollution Effects and Abate- ment", Third International Conference on Water Pollution Research, Section 1, No. 9 , Water Pollution Control Feder- ation, 1 9 6 6 .
C.J. Terhaar, Ewell, W.S., Dziuba, B.S., and Fassett, D.W.,. "Toxicity of Photographic Processing Chemicals to Fish" presented to SPSE Meeting, Chicago, April 22, 1971.
Sollinann, Torald; "Correlation of the Aquarium Goldfish Toxicities o f Some Phenols, Quinones, and other Benzene Derivatives with their Inhibition of Autooxidative Reactions.
110
3 0 .
31.
3 2 .
3 3 ,
34.
3 5 .
36.
3 7 .
3 8 .
3 9 .
40.
41.
42.
4 3 .
44.
45.
?', 11 . Y . T e b b u t t , "Prob lcins of T o x i c E f f l u e n t s " E f f i u c n t a n 3 i t n t c r Trca tmcn t Journal, 6:316-17, 3 1 9 - 2 1 , J u l y , 1 9 6 6 .
G1-cciiwc11, T . X . and B I - C W C ~ , P.E. ; " O p e r a t i o n o f a Two-Staged A e r a t i o n L a g o o n bn P h o t o g r a p h i c Vas t c E f f l u e n t " . a t SPSE c o n f e r e n c e , A p r i l 2 2 , 1 9 7 1 .
P r e s e n t e d
D i s p o s a l o f P h o t o g r a p h i c Was te s , Kodak P u b l i c a t i o n No. 5 - 2 8 , Eastman Kodak C o . , R o c h e s t e r , N e w Y o r k , 14650.
Bobel l , T , W , , "Pollution AbRt@li le l l t i M i n t You Can Do i n t h e Caineraroom" Kodak B u l l e t i n f o r t h e G r a p h i c Arts No, Eastman Kodak Company, 1 9 7 0 .
2 1 ,
H e n d r i c k s o n , T . N . D u r b i n , H . E . , " P h o t o g r a p h i c N a s t e s a s P o l l u t a n t s " C r e d i t L i n e C - P A C , J a n u a r y 1 9 7 1 .
LeFebvre , E . E . and C a l l a h a n , R.A.;"The T o x i c E f f e c t s o f C o l o r P h o t o g r a p h i c P r o c e s s i n g Wastes on B i o l o g i c a l Systems' ' p r e s e n t e d a t SPSE, A p r i l 2 2 , 1971.
Zehnpfenn ig , R . G . , " P o s s i b l e T o x i c E f f e c t s o f C y a n a t e s , T h i o c y a n a t e s , F e r r i c y a n i d e s , F e r r o c y a n i d e s and Chromates on S t r eams" ,
H e n d r i c k s o n , T .N . ; " P o l l u t i o n Problems t h e P h o t o f i n i s h e r Must Face", Photo M a r k e t i n g , J u n e , 1 9 7 0 .
"The P r e p a r a t i o n o r R e g e n e r a t i o n o f a S i l v e r B leach S o l u t i o n b y O x i d i z i n g F e r r o c y a n i d e w i t h P e r s u l f a t e " B . A . H u t c h i n s and L.E. West, J . SMPTE, 6 6 , pp . 764-768, Dec., 1 9 5 7 .
"Method f o r O x i d i z i n g P o t a s s i u m F e r r o c y a n i d e t o Po ta s s ium F e r r i c y a n i d e , " U.S. P a t e n t 1 , 7 3 2 , 1 1 7 , Oct. 1 5 , 1 9 2 9 .
" E l e c t r o l y t i c P r e p a r a t i o n o f A l k a l i Metal F e r r i c y a n i d e , ' ' U.S. P a t e n t 2 ,353 ,781 , J u l y 1 8 , 1944.
" E l e c t r o l y t i c P r e p a r a t i o n o f Sodium F e r r i c y a n i d e , " U.S. P a t e n t 2 ,353 ,782 , J u l y 1 8 , 1 9 4 4 .
"Recove r ing S i l v e r . f rom F i x Ba ths , I 1 Eastman Kodak C o . , Pamphle t #J-lO.
" S i l v e r Recovery f rom Exhaus ted F i x i n g Bath" J . I . C r a b t r e e and J . F . R o s s , T r a n s . o f SMPE , No, 26.
"Automat ic S i l v e r Recovery" K . Hickman, J . o f SMPE, V o l . X V I I , N O . 4 , pp. 591-603, 1931.
" N o n i n s t r u n e n t a l D e t e r m i n a t i o n o f S i l v e r i n F i x i n g Ba ths , " B . A . H u t c h i n s , J . SMPTE, Vol , 7 5 , No. 1, p p . 1 2 - 1 4 , J a n . , 1966 .
111
4 6 .
4 7 .
4 8 .
49.
5 0 .
- . > - .
5 2 .
3 3
!'A S i l v c r Recovery A p p a r a t u s f o r O p e r a t i o n a t High C u r r e n t D e n s i t i e s , " N.J. Cedrone , J . SMPTE, Vol. 67 , Mar. 1958.
"The E l c c t r o l y t i c R e g e n e r a t i o n of F i x i n g Ba ths , I 1 K. Hickman , C . S a n f o r d , 1J. W e y e r t s , Communications H471, Kodak R e s e a r c h L a b o r a t o r i e s .
"Tile A r g e n t o m e t e r - An A p p a r a t u s f o r T e s t i n g f o r a F i x i n g Bath" , N.J. Weyer t s and K . C . D . Hickman, Cc.:Lailnication r f 5 4 S J Kodak R e s e a r c h L a b o r a t o r i e s , 1935.
v e r i n
- - "The Recovery o f S i l v e r f rom E x h a u s t e d F i x i n g Ba ths" , 3 .
C r a b t r e e and J . F . R o s s , C m m u n i c a t i o n # 2 8 0 , Kodak R e s e a r c h L a b o r a t o r i e s .
I .
" E l e c t r o l y s i s o f S i l v e r B e a r i n g T h i o s u l f a t e S o l u t i o n s ' ' K . i-iickman, 'd. lv'eyerts , O . E . G o e h l e r , I n d u s t r i a l and E n g i n e e r i n g Zhe in i s r ry , V o l . 25 , p . 202, Feb, 1933 .
" E l e c t r o l y s i s o f Complex S i l v e r S a l t S o l u t i o n s " D r . T i b o r Erdey-Gruz and D r . V a r e r i a H o r v a t h y , Magyar Kim-Lap,@, 4, p p . 5 2 4 - 5 3 1 , 1949 , i3udapest U n i v e r s i t y o f S c i e n c e .
" E l e c t r o l y t i c Recovery o f S i l v e r f rom F ix i i l g B a t h s a t La.. . < u r r e n t D e n s i t y " A . A . Rasch and J . I . C r a b t r e e , ?hotogr;p:.s .
S c i e n c e and T e c h n i q u e , S e r i e s I I , V o l . 2 , No. 1, pp 1 " e p . 195- b .
3;
' E l e c t r o l y t i c Recovery of S i l v e r f rom Used F i x e r Bath" H . X i s e n b r e y and U. F r i t z e , R o n t g e n p r a x i s , V o l . 1 9 , 3 0 . 11, p p . 2 8 4 - 3 0 2 , 1966 .
54. "The Problem o f S i l v e r Recovery f r o m E x h a u s t e d Fixi .*g S o l u t i o n s ' ' G . A . Namias, P r o g r e s s 0 F o t o g r a f i c o , 44, No. 7 , p p . 2 7 2 - 2 7 4 , J u l y 1939.
5 5 . " E l e c t r o d e s p o s i t i o n o f S i l v e r w i t h Superimposed A l t e r n a t l n g C u r r e n t " Lar i ssa Domnikov, Me ta l F i n i s h i n g , G3, p p . 6 2 - 6 6 , 1965 .
5 6 . " E l e c t r o l y t i c S i l v e r Recovery - A Survey ' ' D . C . B r i t t o n , B r i t i s h Kinematography, V o l . 45 , No. 1, J u l y 1 9 6 4 .
5 7 . " E l e c t r o l y t i c Recovery o f S i l v e r " M . C . K i n s l e r , ?hotograpI;-; P r o c e s s i n g , V o l . 3 , No. 6 , J u n e / J u l y , 1968.
I
58. "Recovery o f S i l v e r f rom Wash Wate r s by i o n i c Exchange Chromotography" A . B . Dcvankov, V.M. i a u f e . , A . A . >f i ronon , T.S. S i s h u n o v a , Zhurna l Nauchnoi , P r i k l a d n o i F o t o g r a f i i K i n e m o t a g r a f f i , 1 3 , p p . 1 4 - 1 9 , 1968 .
I
5 9 . " A S i l v e r - R e c o v e r y A p p a r a t u s f o r O p e r a t i o n a t High C u r r e n t D e n s i t i e s " N . J. Cedrone , SMPTE, V o l . 6 7 , No. 3 , pp . 1 7 2 - 1 7 4 , March 1 9 5 8 .
112
60.
6 1 .
62 .
6 3 .
64.
6 5 .
6'6 . 67.
6 8 ,
69 .
70.
7 i .
7 2 .
7 3 .
74.
7 5 .
76.
77.
78.
. A , ' 'Tiie Recovery o f S i l v e r f rom Exhaus tcd F i x i n g B a t h s " J C 1 - ~ i b t 1 ' e e and J . F . R o s s , ,4merican Annual o f Photography!- 1927.
"The R e c o v e r y o f S i l v e r f rom F i x i n g Baths b y t h e E l e c t r o l y t i c blcthod" C e s a r e d e b l i t r i , F e r r a n i a A - Magaz ine , V o l . XI1 , No, 1, 1964.
' :Ext rac t ion of C o l l o i d a l S i l v e r S u l f i d e f rom i t s Hydroso l b y E m u l s i f i c a t i o n " L . D . S k r y l e v , V . I . B o r i s i k h i n a , S .G. J l l k r u s h i n , Z h u r n a l . P r i k l a . d n o i K h i m i i , V o l . 37 , No . 3 , pp 693- 6 9 5 , Narch 1964.
T
U.S. P a t e n t 1 , 8 6 6 , 7 0 1 : Method and A p p a r a t u s f o r Recove r ing S i l v e r froin F i x i n g S o l u t i o n s .
U .S . P a t e n t 476 ,985: P r o c e s s and A p p a r a t u s f o r t h e E l e c t r o l y s i s o f P h o t o g r a p h i c F i x i n g S o l u t i o n s .
U.S. P a t e n t 2 , 4 9 3 , 3 9 6 : Recovery o f S i l v e r f rom S o l u t i o n s o f S i l v e r S a l t s .
U.S. P a t e n t 2 , 5 0 3 , 1 0 4 : P r o c e s s f o r P r e c i p i t a t i n g S i l v e r f rom S o l u t i o n .
U.S. P a t e n t 2 , 5 0 7 , 1 7 5 : S i l v e r Recovery .
U.S. P a t e n t 2 , 5 2 9 , 2 3 7 : E1 ,ec t ro -Recovery o f M e t a l s .
U.S. P a t e n t 2 , 5 4 5 , 2 3 9 : Recovery o f Gold o r S i l v e r .
U.S. P a t e n t 2 , 5 7 9 , 5 3 1 : P r o c e s s f o r E x t r a c t i n g Gold'or S i l v e r
U.S. P a t e n t 2 ,607 ,721 : S i l v e r Recovery f r o m Sodium T h i o - s u l f a t e S o l u t i o n s .
U.S. P a t e n t 2 , 6 1 2 , 4 7 0 : S e l e c t i v e E l e c t r o d e p o s i t i o n o f S i l v e r .
U.S. P a t e n t 2 , 6 1 9 , 4 5 6 : M e t a l Recovery A p p a r a t u s .
U.S. P a t e n t 2 , 7 9 1 , 5 5 6 : A p p a r a t u s f o r the Recovery o f S i l v e r f rom P h o t o g r a p h i c P r o c e s s i n g B a t h s .
U.S. P a t e n t 2 , 9 0 5 , 3 2 3 : A p p a r a t u s f o r t h e Recovery o f S i l v e r f rom S p e n t P h o t o g r a p h i c S o l u t i o n s .
U.S. P a t e n t 2 ,934 ,429 : S i l v e r Recovery P r o c e s s .
U . S . P a t e n t 3 , 0 0 3 , 9 4 2 : E l e c t r o l y t i c C e l l For Recovery o f S i l v e r from S p e n t P h o t o g r a p h i c F i x i n g B a t h s .
U.S. P a t e n t 3 ,082 ,079 : S i l v e r Recovery f r o m P h o t o g r a p h i c F i x i n g S o l u t i o n s ,
113
79. U . S . P n t c n t 3 , 9 4 3 , 4 3 2 : A p p a r a t u s for Recovery o f S i l v e r f roin S p e n t P h o t o g r a p h i c S o l u t i o n s .
8 0 . U.S. P a t e n t 3 , 3 1 1 , 4 0 8 : S i l v e r Recovery P r o c e s s .
81. S c h r e i b e r , bl. L . , “ P ; e s e n t S t a t u s of S i l v e r Recovery i n t h e b l o t i o n P i . c t u r e I n d u s t r y , : J . SMPTE, V o l . 7 4 , J u n e 1 9 6 5 .
1 1 4
SECTIOS ;i
GLOSSARY
Absorbance - The n e g a t i v e loglo o f t h e p e r c e n t t r a n s m i s s i o n o f r a d i a n t e n e r g y .
Aerob ic - R e q u i r i n g , o r n o t d e s t r o y e d by , t h e p r e s e n c e of f r e e e l e m e n t a l oxygen.
Anode - The p o s i t i v e e l e c t r o d e o f a n e l e c t r o l y t i c c e l l where o x i d a t i o n o c c u r s , - - BOD - A b b r e v i a t i o n f o r b i o c h e m i c a l oxygen demand, oxygen used i n t h e b i o c h e m i c a l o x i d a t i o n of o r g a n i c m a t t e r i n a s p e c i f i e d t i m e , a t a s p e c i f i e d t e m p e r a t u r e , and under s p e c i f i e d c o n d i t i o n s .
The q u a n t i t y o f
Cathode - The n e g a t i v e e l e c t r o d e of an e l e c t r o l y t i c c e l l where ‘ r e d u c t i o n o c c u r s .
C h l o r i n a t i o n - The a p p l i c a t i o n of c h l o r i n e t o w a t e r o r w a s t e w a t e r , g e n e r a l l y f o r t h e p u r p o s e of d i s i n f e c t i o n , b u t f r e q u e n t l y f o r a c c o m p l i s h i n g o t h e r b i o l o g i c a l o r chemica l r e s u l t s .
C h l o r o x - - R e g i s t e r e d t r a d e mark, Chlorox Corp . , Oakland , C a l i f o r n i a ; c o n t a i n s 5 % sodium h y p o c h l o r i t e by w e i g h t .
C l a r i t y - The i n v e r s e o f a b s o r b a n c e .
- C O D - A b b r e v i a t i o n f o r c h e m i c a l oxygen demand. A measure o f t h e oxygen - consuming c a p a c i t y o f i n o r g a n i c and o r g a n i c m a t t e r ? r e s e n t i n w a t e r o r w a s t e w a t e r . It i s e x p r e s s e d a s t h e amount o f oxygen consumed from a chemica l o x i d a n t i n a s p e c i f i c t e s t . I t does n o t d i f f e r e n t i a t e between s t a b l e and u n s t a b l e o r g a n i c m a t t e r and t h u s does n o t n e c e s s a r i l y c o r r e l a t e w i t h b i o c h e m i c a l oxygen demand. A l s o known a s OC and D O C , oxygen consumed and d i c h r o m a t e oxygen consumed, r e s p e c t i v e l y .
Complex Cyanide - F e r r o c y a n i d e { F e (CN) 6-4) a n d / o r f e r r i c y a n i d e XFe ( C N ) 6 - 3 ) .
C o n c e n t r a t i o n P o l a r i z a t i o n - The p r o d u c t i o n of any i r r e v e r s i b l e p o t e n t i a l a t t h e s u r f a c e o f an e l e c t r o d e by change of i o n i c co’n- c e n t r a t i o n i n t h e immedia te v i c i n i t y of t h e e l e c t r o d e .
Conver s ion - The o x i d a t i o n of f e r r o c y a n i d e t o f e r r i c y a n i d e .
I Coulomb - The c u r r e n t p a s s e d when 1 amp f l o w s f o r 1 s e c o n d .
C u r r c n t c l c x i - + \ * ~ . i i i - i - ~ \ n t p e r u n i t a r e a o f e l e c t r o d e s u r f a c e .
1 1 5
I
Current density ratio - The ratio o f current-density of the cathode to the current density of the anode.
Cuvette - A cell used for spectrophotometric measurement.
Electrolysis - Affecting a chemical change by means o f an applied electric current.
Equivalent weight - The amount of a substance which reacts with one Faraday; usually the formula weight divided by the valence.
Farad3 - An amount o f electricity equal to 96,487 coulombs --Z-c) . Flocculation - In water and wastewater treatment, the agglomeration of colloidal and finely divided suspended matter after coagulation by gentle stirring by either mechanical or hydraulic means.
F-low Study - A centrifugation study in which the rotor speed remains constant while the f l o w rate is varied.
I o n permeable membrane - A membrane which allows only select ions to pass through.
K - 1 2 F Bleach - Ferricyanide bleach used in processing Kodachrome reversal f i l m .
Kodachrome - Trade name for color film manufactured by the Eastman Kodak C o .
Oxidation - The process by which atoms of an element lose electrons. Ozonation - Affecting a chemical change by means of ozone.
Photochemical - Achemical reaction catalyzed by light. Prussian Blue - Ferric ferrocyanide. Reduction - The process by which atoms of an element gain electrons.
Regeneration - The oxidation of ferrocyanide to ferricyanide.
Stoichiometric - Pertaining to or involving substances which are in the exact proportions required for a given reaction.
Supernatant - The liquid standing above a sediment or precipitate.
-Synergism - The improvement in performance achieved because two agents are working together.
116
.
a
l ! ; c o i . c t i c c i l O i y s c n ilcmond (TOP) - T h e t h c o r e t i c a l amount o f o ~ y g c i i t W L o u l i i b c consumed i f a c h e m i c a l were to be oxidized t o t h e highest oxidation state of each element in the compound. (i.e. CO2, HzO, etc.)
Toxicity - The quality of being poisons.
Abbreviations Used
g - grams
1 - liters
Nin - minutes
-
- 3 - milligrams
nl - milliliters
- - millimicrons (10-9 meters) = nm (nanometers)
-
ppm - parts per million - mg/l (milligrams per liter)
117
S E C T I O N XI
APPENDICES
Page No.
A Reagents Used in Various Ferro-Ferricyanide Analysis Procedures
hlethod of Analysis of Ferrocyanide in the Presence of Ferricyanide
C Centrifugation Procedure
D Detailed Analytical-Procedures
E
B
The Photographic Process and Sources o f Pollution
1 2 0
1 2 1
122
123
1 2 7
134
135
Figure E-1
Table E-1 Steps in Color Process
Table E - 2 Ions or Compounds Found in Black-and-
Ektachrome Reversal Film Process
136 White and Color Processing Solutions
Table E-3 Approximate Chemical Concentrations in Effluents from Photo Processing
139 Machines
Table E-4 BOD of Chemicals Used in Photographic 141
Table E - 5 Relative Ineffectiveness of Biological
Processing
Type of Treatment of Photographic Chemicals 142
143 F Waste Treatment Facilities Presently in Use
Table F - 1 Concentration of Chemicals in Waste Effluent at Typical Photo- finishing Plants 149
150 Table F - 2 Chemicals Removed by Treatment
119
APPENDIX A
Reagents Used in Various Fcrro - Ferricyanide Analysis Procedures
Reagents Used Procedures in Which Reagents Are Used
1) 0.6 EIolar Potassium Iodide (49.8 gm K I / 5 0 0 ml)
2 ) Zinc Sulfate-Sulfuric acid reagent (125 gm ZnSO 7H 0, dissolved in 7.0 N H 2 S O 4 &luge to s o 0 ml)
t-'
0 N 3 ) 0.100 Normal Sodium thiosulfate
(24.82 gm Na2S203' 5H20/liter
4 ) Starch Solution: 1.0 gm starch (in 10 cc cold H 0, stir into 2 0 0 cc boiling water) 2
5) 2.5 Normal Sodium Hydroxide (110 g"
6 ) Ferrous - Ferric reagent ( . 7 5 gm FeC12) 20 ml H 0 (distilled) ( . 7 5 gm FeC13) 3.0 ml 6 CL - dilute to 30 ml
7) 7.0 Normal Sulfuric Acid
8) 0 . 0 5 0 Ceric sulfate (26.4 gm/l)
1) Cerimetric determination-of ferricyanide
2 ) Cerimetric determination of ferricyanide
3) Cerimetric determination of ferricyanide
4 ) Cerimetric determination of ferricyanide
5) Spec t roplio t ome t r ic de t e rmina t ion f e r ro - cyanide
6) Spectrophotometric determination of ferro- cyanide (modified Kodak method)
7) Cerimetric and potentiometric determination
8) Cerimetric determination of ferrocyanide ferrocyanide
* Lr +
APPENDIX B
Method o f A n a l y s i s o f F e r r o c y a n i d e
i n t h e P r e s e n c e o f F e r r i c y a n i d e
1) C o n c e n t r a t i o n o f f e r r i c y a n i d e m e a s u r e d 4 ) C i l c u l a t e c o n t r i b u t i o n t o t o t a l 2’0 r r u s i n g a b s o r b a n c e a t 417 mu. (Column 1 a n d 2 ) al , r , r b a n c e due t o f e r r o c y a n i d e .
( c ~ ~ l t i i r i n 3 minus co lumn 4 l i s t e d in 2) S i n c e b o t h f e r r o - a n d f e r r i c y a n i d e a b s o r b co L t i y i n 5)
a t 2 2 0 mp, a b s o r b a n c e a t 2 2 0 m p i n c l u d e s c o n t r i b u t i o n f r o m b o t h . (co lumn 3) 5) C l :( i l<ite c o n c e n t r a t i o n o f fe r roc ,yn:* i i ld
i i - : r i p a b s o r b a n c e a t 2 2 0 m p 3 s shc>,.i? i n 3) C a l c u l a t e c o n t r i b u t i o n t o t o t a l 220 m p c ~ l u r n r i 5 ( co lumn 6 )
a b s o r b a n c e due t o f e r r i c y a n i d e (coulmn 4 ) ( 1 0 0 g m / l f e r r i c y a n i d e h a s a n a b s o r b a n c e of 1 . 5 2 a t 2 2 0 mu )
Below i s a s a m p l e r u n u s i n g known c o n c e n t r a t i o n s o f f e r r o and f e r r i c y a n i d e . 1 2 3 4 5 6 7
Total C a l c u l a t e d T o t a l A b s o r b a n c e Ab s o r b anc e C a l c u l a t e d A c t u a l c o n c e n - A b s o r b a n c e C o n c e n t r a t i o n A b s o r b a n c e d u e t o due t o C o n c e n t r a t i o n t r a t i o n m g / l
a t 417 m p F e r r i c y a n i d e a t 2 2 0 mp F e r r i c y a n i d e F e r r o c y a n i d e F e r r o c y a n i d e f e r r i f c r r o - ~ _ _ _ ._
a t 2 2 0 mp a t 2 2 0 mi l a t 2 2 0 mp ___- mg/ 1
1 . 4 0 316 2 9 . 5 5.00 2 4 . 5 236 3 2 0 2 5 6
. 3 7 8 3 8 . 1 1 . 2 0 6 . 9 0 6 5 8 0 6 4
.09 5 20 1 . 9 5 .36 1 . 5 9 1 5 2 0 1 6
. 0 4 8 1 0 1 . 0 0 . 1 7 - 8 3 8 1 0 8
.72 162 1 5 . 1 2 . 4 5 1 2 . 5 5 1 2 1 1 6 0 12s
. 1 a6 4 1 4 . 0 . -60 3 . 4 0 33 4 0 32
APPENDIX C
C e n t r i f u g a t i o n P r o c e d u r e
A. S t a r t c e n t r i f u g e and slowly i n c r e a s e r o t o r s p e e d t o 6 5 0 0
B. F i l l c o l l e c t i o n t u b e s f rom c a r b o y a t 25 ml/min. When t u b e s
rpm. ( N a n u f a c t u r e r ' s recommended minimum s p e e d )
a r e f i l l e d , s t o p f l o w and a l l o w c e n t r i f u g e t o r u n f o r f i v e m i n u t e s t o s t a b i l i z e t u b e c o n t e n t s ,
C . R o t o r S t u d y ( C o n s t a n t Flow)
1) On t h e i n i t i a l r u n f o r e a c h m e t a l , a c o n s t a n t f l o w o f 2 5 ml/min was u s e d ; on s u b s e q u e n t r u n s , t h e optimum f l o w from t h e p r e v i o u s r u n was u s e d .
2 ) S t a r t f l o w and a l l o w t o r u n f o r two m i n u t e s a t 6 5 0 0 rpm, t a k e a 1 0 m l s ample and s h u t o f f f l o w .
Slowly i n c r e a s e r o t o r s p e e d t o n e x t s t e p and a l l o w two m i n u t e s f o r s t a b i l i z a t i o n .
3)
4)
5) When maximum s p e e d h a s b e e n r e a c h e d , f o l l o w same p r o c e d u r e
S t a r t f l o w and a l l o w t o r u n f o r two m i n u t e s b e f o r e t a k i n g sample . S h u t o f f f l o w and i n c r e a s e r o t o r s p e e d .
d e c r e a s i n g r o t o r s p e e d s t e p w i s e .
D. Flow S tudy ( C o n s t a n t R o t o r Speed)
1) Flow s t u d y f o r e a c h meta l c a r r i e d o u t a t t h e optimum r o t o r s p e e d f o r t h e p a r t i c u l a r me ta l and f l o c c u l a n t c o n c e n t r a t i o n .
2 ) A f t e r r o t o r s p e e d h a s b e e n o b t a i n e d , a l l o w f i v e m i n u t e s f o r s t a b i 1 i za t i o n .
3) S t a r t f l ow a t 6 ml/min and a l l o w t o r u n f o r f o u r m i n u t e s (two minu tes i n a l l o t h e r c a s e s ) and t a k e a 1 0 m l s ample S h u t o f f f l o w f o r 2 m i n u t e s .
4)
5 ) When-maximum f l o w r a t e h a s been r e a c h e d , f o l l o w same
S t a r t f l ow a t n e x t h i g h e r r a t e and r u n f o r two m i n u t e s b e f o r e t a k i n g s a m p l e .
p r o c e d u r e , d e c r e a s i n g f l o w r a t e s t e p w i s e .
1 2 2
A P P E N D I X D
D e t a i l e d , A n a l y t i c a l P r o c e d u r e s
P o t e n t i o i i i c t r i c d e t e r m i n a t i o n of f e r r o c y a n i d e i n p r o c e s s K - 1 2 F b l e a c h ( 2 2 )
Add 2 5 0 m l o f d i s t i l l e d w a t e r t o a 4 0 0 m l b e a k e r and p l a c e on a magne t i c s t i r r e r a t s l o w speed u s i n g a magnetic stirring b a r ,
P i p e t ( h e l d v e r t i c a l l y ) 5 . 0 m l of sample i n t o t h e b e a k e r .
Add 1 0 d r o p s 0.010 N Sodium D i p h e n y l a m i n e s u l f o n a t e i n d i c a t o r .
P l a c e e l e c t r o d e s f rom a p H - m i l l i v o l t m e t e r i n t o s o l u t i o n .
T i t r a t e s o l u t i o n , f rom a 50 m l b u r e t t e , w i t h 0 , 0 5 0 N Ceric s u l f a t e i n 0 . 5 m l a l i q u o t s , r e c o r d i n g b o t h b u r e t t e and m t e r r e a d i n g s .
F i n d e n d p o i n t by d e l t a method
C a l c u l a t i o n : 4.84 x (ml) o f 0 . 0 5 0 c e r i c s u l f a t e added a t e n d p o i n t ) = g r a m s / l i t e r of Na4Fe(CN)6'10 H20 i n s ample .
I o d o m e t r i c d e t e r m i n a t i o n o f f e r r i c y a n i d e i n p r o c e s s K - 1 2 F B leach (23)
P i p e t 5 . 0 ml of sample and 5 m l o f d i s t i l l e d w a t e r i n t o a 2 5 0 in1 Er lenmeyer f l a s k , and p l a c e on a m a g n e t i c s t i r r e r a t slow s p e e d .
P i p e t 25 ml of 0 .6 M p o t a s s i u m i o d i d e s o l u t i o n and 2 0 m l o f z i n c s u l f a t e - s u l f u r i c a c i d r e a g e n t . (See Appendix A)
T i t r a t e w i t h 0.100 N sodium t h i o s u l f a t e u n t i l c o l o r changes t o p a l e y e l l o w .
P i p e t 5 m l o f s t a n d a r d s t a r c h s o l u t i o n i n t o t h e f l a s k .
Con t inue t i t r a t i o n u n t i l t h e b l u e c o l o r d i s a p p e a r s .
C a l c u l a t i o n : 5 .6 x (ml o f 0 . 1 0 0 N Na S 0 added a t e n d p o i n t ) - g r a m s / l i t e r Na3 Fe(CN),'iA Jample .
I o d o m e t r i c D e t e r m i n a t i o n of f e r r i c y a n i d e i n K - 1 2 F Bleach (B)
Using an u p r i g h t p i p e t , add 5 . 0 ml sample and 5 m l d i s t i L l e d w a t e r t o a 2 5 0 m l Er lenmeyer f l a s k .
P l a c e on magne t i c s t i r r e r and s t i r a t low s p e e d .
P i p c t 1 0 ml o f 0 . 7 M z i n c ace t c i t e s o l u t i o n and 20 ml o f 3 .0M sodium a c e t a t e b u f f e r i n t o t h e f l a s k .
123
I
A d ~ l 5.0 g r a ~ n s of potassium iodide crystals to t h e solution and dissolve.
Rinse down t h e inside of the flask with distilled water and i~iililediately titrate with 0.100 N sodium thiosulfate solution to p a l e yellow.
Add 5 ml of a standard starch indicator solution and continue titrating until blue color disappears.
Record b u r e t t e r e a d i n g ,
Calculation: 5 . 6 x (ml 0.100 N sodium thiosulfate) =I gm/liter sodium ferricyanide.
Cerimetric Determination of Ferrocyanide in K - 1 2 F Bleach
Add 250 ml distilled water to a 400 ml beaker.
Using an upright pipet add 5.0 ml o f sample to the beaker.
Pipet 10 ml of 7.0 N sulfuric acid to the beaker.
(24)
Add 10 drops of sodium.diphenylamine-sulfonate indicator solution.
Place on magnetic stirrer and titrate with 0.050 ceric s u l f a t e solution.
Record burette reading.
Calculation: 4.84 x (ml 0.050 ceric sulfate) = gm/liter- sodium ferrocyanide.
Spectrophotometric Determination of Ferrocyanide, Modified Kodak Nethod
Using an upright pipet add 10.0 ml of sample to a 100 ml volumetric flask and dilute to volume with distilled water.
Stopper flask and shake to mix the solution thoroughly.
Acidify the solution with concentrated hydrochloric acid (using pH indicator paper) to pH 3 - 4 .
Take 40 ml of the acidified solution and add 2 drops of the ferrous-ferric reagent. Stir immediately.
A l l o w sample to stand for fifteen minutes without further agitation to develop blue color,
Fill one spectrophotometer cell with the solution to which the ferrous-ferric reagent was added.
124
I Fi l l 3 ~ i i . ~ t ~ l l l l l g c c l l w i t h t h e s o l u t i o n t o which t h e f e r r o u s - i c r 1 - i ~ r c a g e n t was n o t added . T h i s i s t h e b l a n k s o l u t i o n .
i Insert b o t h c e l l s i n t o a s p e c t r o p h o t o m e t e r and z e r o t h e b l a n k a t 7 0 0 nm.
bn
Tic
Neasu re t h e a b s o r b a n c e o f t h e b l u e sample a t 7 0 0 nm on t h e s p e c t r o p h o t o m e t e r . * C a l c u l a t i o n : 2 2 . 4 x (Absorbance a t 7 0 0 nm) x ( d i l u t i o n f a c t o r )
* I f a b s o r b a n c e of b l u e s o l u t i o n i s g r e a t e r t h a n 0 . 8 , d i - l u t e 1 0 . 0 ml of t h e a c i d i f i e d sample t o 1 0 0 m l and r e p e a t . I f s o l u t i o n does n o t v i s u a l l y t u r n b l u e r e p e a t t e s t w i t h o u t d i l u t i n g sample.
m g / l i t e r sodium f e r r o c y a n i d e .
S p e c t r o p h o t o m e t r i c D e t e r m i n a t i o n o f F e r r i c y a n i d e a t 4 1 7 nm
F i l l one s p e c t r o p h o t o m e t e r c e l l w i t h t h e s o l u t i o n t o b e a n a l y z e d .
F i l l a ma tch ing c e l l w i t h d i s t i l l e d w a t e r , T h i s c e l l i s t h e b l a n k .
P l a c e b o t h c e l l s i n t h e s p e c t r o p h o t o m e t e r and z e r o t h e blank a t 4 1 7 nm.
Measure t h e a b s o r b a n c e o f t h e sample a t 4 1 7 nm on t h e s p e c - t r o p h o t o m e t e r . *
C a l c u l a t i o n s : 296 x (Absorbance a t 4 1 7 nm) ( d i l u t i o n f a c t o r ) =
S p e c t r o p h o t o m e t r i c D e t e r m i n a t i o n o f Sodium F e r r o c y a n i d e a t 2 2 0 nm
F i l l one s p e c t r o p h o t o m e t e r c e l l w i t h t h e s o l u t i o n t o b e a n a l y z e d .
F i l l a ma tch ing c e l l w i t h d i s t i l l e d water .
P l a c e b o t h c e l l s i n t h e s p e c t r o p h o t o m e t e r and z e r o t h e b l a n k a t 2 2 0 nm.
m g / l i t e r sodium f e r r i c y a n i d e .
T h i s i s t h e b l a n k .
Measure t h e a b s o r b a n c e o f t h e sample a t 2 2 0 nm on t h e s p e c t r o - p h o t o m e t e r . *
C a l c u l a t i o n : 1 6 . 7 x (Absorbance a t 220 nm) x ( d i l u t i o n f a c t o r )
* I f t h e a b s o r b a n c e i s g r e a t e r t h a n 0 . 8 d i l u t e 1 0 . 0 m l o f g a m p l e t o 1 0 0 m l and r e p e a t t h e t e s t .
mg/l sodium f e r r o c y a n i d e
125
S p c c t r o p h o t o n e t r i c D e t e r m i n a t i o n o f Fer r - ic -yanide a t 4 6 0 . 5 nm
F i l l one s p e c t r o p h o t o m e t e r c e l l w i t h t h e s o l u t i o n t o b e a n a l y z e d .
F i l l a match ing c e l l w i t h d i s t i l l e d water . T h i s i s t h e b l a n k .
P l a c e b o t h c e l l s i n t h e s p e c t r o p h o t o m e t e r and z e r o t h e b l a n k a t 4 6 0 . 5 nm.
Neasu re t h e a b s o r b a n c e o f t h e sample a t 4 6 0 , s nm on t h e s p e c t r o - pho to ine te r . * C a l c u l a t i o n : 2 . 8 5 x (Absorbance a t 4 6 0 . 5 nm) x ( d i l u t i o n f a c t o r ) =
* I f t h e a b s o r b a n c e i s g r e a t e r t h a n 0 . 8 d i l u t e 1 0 . 0 m l o f sample t o 1 0 0 ml and r e p e a t t h e t e s t .
g / 1 sodium f e r r i c y a n i d e . I I !
P r e p a r a t i o n o f F e r r o - f e r r i R e a g e n t
I D i s s o l v e i n 2 0 ml o f d i s t i l l e d water 0 . 7 5 0 g f e r r i c c h l o r i d e and 0 . 7 5 0 g f e r r o u s c h l o r i d e .
Ahd 3 m l c o n c e n t r a t e d h y d r o c h l o r i c a c i d . I
D i l u t e t o 30 ml w i t h d i s t i l l e d water .
APPENDIX: E
The P h o t o g r 3 p h i c P r o c e s s 3nd S o u r c e s o f P o l l u t i o n
The c o l o r r e v e r s a l Ektachroinc p h o t o g r a p h i c p r o c c s s w a s t e e f f l u - e n t i s r e p r c s c n t a t i v e o f p o l l u t i o n problems from t h e p h o t o g r a p h i c i n d u s t r y , b e c a u s c i t c o n t a i n s all t h e t y p i c a l p r o c e s s i n g s o l u t i o n s . The f i l m t r a v e l s t h r o u g h t h e s e r i e s of b a t h s , a s shown i n F i g u r e E - 1 , ( page 1 3 4 ) . Thesc i n c 1 u d e : t h e p r e h a r d e n e r , n e u t r a l i z e r , 1 s t d c v e l o p o r , 1 s t s t o p , w i l to r wash, c o l o r doveloper, 2nd s t o p , w a t e r wash , b l e a c h , f i x e r , w a t e r wash and s t a b i l i z e r .
The f u n c t i o n s of each o f t h e s e s o l u t i o n s a r e d e s c r i b e d i n Tab le E-1.
I t s h o u l d be n o t e d t h a t c o m b i n a t i o n s o f t h e s e s o l u t i o n s a r e used t o make up a l l o t h e r ma jo r p h o t o g r a p h i c p r o c e s s e s . For example, t h e p r o c e s s i n g of c o l o r n e g a t i v e f i l m c o n s i s t s of a c o l o r d e v e l o p e r , s t o p f i x , b l e a c h , f i x and s t a b i l i z e r . a s i m i l a r c o m p o s i t i o n a s t h e c o r r e s p o n d i n g s o l u t i o n s i n t h e Ek ta - chrome p r o c e s s . However, s i n c e t h e s o l u t i o n s t h a t a r e used i n
* t h e s e o t h e r p r o c e s s e s a r e a l l c o n t a i n e d i n t h i s s i n g l e p r o c e s s , t h e Ektachrome p r o c e s s i s d i s c u s s e d h e r e . Any c i t e d problem, w i t h a p a r t i c u l a r s o l u t i o n i n t h a t p r o c e s s , w o u l d t h u s , be a n a l o g o u s t o a p rob lem w i t h t h e same s o l u t i o n i n a n o t h e r p r o c e s s .
These s o l u t i o n s a r e of
T a b l e E - 2 shows t h e r a n g e o f i n d i v i d u a l c h e m i c a l s c o n t a i n e d i n t h e p r o c e s s i n g s o l u t i o n s men t ioned p r e v i o u s l y . h a s b e e n p u b l i s h e d by t h e Eastman Kodak Co.
T h i s i n f o r m a t i o n
T a b l e E - 3 l i s t s t h e a p p r o x i m a t e a v e r a g e c o n c e n t r a t i o n o f i n - d i v i d u a l c h e m i c a l s c o n t a i n e d i n t h e v a r i o u s p h o t o g r a p h i c p r o - c e s s e s . i c a l may b e c o n t a i n e d i n a-number o f p h o t o g r a p h i c p r o c e s s e s ; some i n a l l .
Here i t can r e a d i l y b e s e e n t h a t any one s p e c i f i c chem-
T a b l e E - 4 l i s t s t h e p r i m a r y c h e m i c a l s d i s c h a r g e d f rom t h e pho to - g r a p h i c p r o c e s s t h a t a r e o r g a n i c and t h u s , w o u l d e x e r t an oxygen demand when d i s c h a r g e d t o t h e e n v i r o n m e n t . T h i s l i s t was t a k e n f rom Kodak Pamphlet 5 - 2 8 e n t i t l e d , " D i s p o s a l of P h o t o g r a p h i c Wastes" . A pr imary c o n c e r n i s t h e s p e c i f i c c h e m i c a l s t h a t show a s m a l l f i v e - d a y b i o c h e m i c a l oxygen demand (BOD5) upon - t e s t i n g , b u t a c t u a l l y r e q u i r e a l a r g e amount o f oxygen t o b e t o t a l l y o x i d i z e d t o i n e r t end p r o d u c t s o f c a r b o n d i o x i d e and w a t e r . The f o l l o w i n g g e n e r a l r e a c t i o n d e s c r i b e s wha t i s t e rmed T h e o r e t - i c a l Oxygen Demand (TOD):
The T O D t h u s r e p r e s e n t s t h e t o t a l u l t i m a t e oxygen demand upon t h e e n v i r o n m e n t . A compar ison o f t h e TOD t o t h e BOD5 of t h e i n d i v i d u a l chemica l g i v e s an i n d i c a t i o n o f t h e r e l a t i v e b i o - d e g r a d a b i l i t y o f t h e c h e m i c a l .
127
T ~ b l e E - 5 l i s t s t h e number and p e r c e n t a g e o f t h e 4 5 c h e m i c a l s shown i n T a b l e E - 4 i n c a t e g o r i e s o f t h e p e r c c n t a g c r a t i o of 30Dj t o T O O . 7 0 % o f t h e c h e m i c a l s had 3 BODS l e s s t h a n 1 5 o f t h e i r T O D ; I 'o r 51.2; O C t h c c h e m i c a l s , i t was l e s s t h a n 1 0 % . T h i s i i i c~ i i~s ~ i ~ ~ i ' ~ 1 I * tiic'se c l icmica ls were t r e a t e d i n a m u n i c i p a l
A d i s c u s s i o n of t h e s p e c i f i c p o l l u t a n t chemica l s c o n t a i n e d i n each o f t h e p r o c e s s i n g solutions (as listed in Table E-2) follows: P r e h a r d e n e r I
The p r i m a r y c h e m i c a l s o f c o n c e r n i n a p r e h a r d e n e r a r e aluminum and fo rma ldehyde ; a l t h o u g h n e i t h e r i s c o n s i d e r e d t o b e r e l a t i v e l y
and w a t e r i n a m u n i c i p a l s e c o n d a r y t r e a t m e n t p l a n t , o r w i t h a s t r o n g chemica l o x i d a n t .
Black-and-Whi te D e v e l o p e r s
Hydroquinone and E l o n d e v e l o p i n g a g e n t s i n t h e b l a c k - a n d - w h i t e d e v e l o p e r s a r e b o t h h i g h l y t o x i c t o f i s h , i f d i s c h a r g e d i n t o s t r e a m s . When t e s t e d t o i n d i g e n o u s c a r p ( c y p r i n i d i a ) , Mohanroa, ( 2 7 )
I
t o x i c . Formaldehyde c a n b e e a s i l y o x i d i z e d t o c a r b o n d i o x i d e I
i e t . a l . , found t h a t hydroqu inone and e l o n were t o x i c ( caused f i f t y i p e r c e n t o f a f i s h p o p u l a t i o n t o d i e ) a t 0 . 3 mg/l and 5 mg/l I r e s p e c t i v e l y . However, i n c o m b i n a t i o n t h e c h e m i c a l s showed a I
i
I
s y n e r g i s t i c e f f e c t and t h e e f f l u e n t became t o x i c a t l ower con- c e n t r a t i o n s o f e a c h . T e r h a a r ( 2 8 ) e t . a l . , r e p o r t e d t h a t h y d r o - qu inone and e l o n were e q u i t o x i c a t 0 . 1 mg/l.
Sollman ( 2 9 ) showed t h a t , "Hydroquinone when added t o t h e aquar ium w a t e r was found t o b e a b o u t a hundred t i m e s more t o x i c t h a n p h e n o l , t o g o l d f i s h (and t o Daphnia magna), b u t i s o n l y a b o u t t w i c e a s t o x i c when i n j e c t e d i n t o f i s h o r mammals." West ( 1 0 ) r e p o r t s t h a t , " F o r t u n a t e l y , hydroqu inone i s q u i c k l y b i o d e g r a d e d i n a w a s t e - t r e a t m e n t p l a n t " .
C o l o r Developers
No s p e c i f i c p o l l u t a n t e f f e c t s have been n o t e d f o r c o n s t i t u e n t s in t h e c o l o r d e v e l o p e r s o l u t i o n , r e l a t i v e t o t o x i c i t y t o f i s h and b i o l o g i c a l o r g a n i s m s . Benzyl a l c o h o l i s o n l y s l i g h t l y t o x i c t o f i s h ( i n t h e r a n g e o f 1 t o 1 0 0 m g / l ) , b u t t h e c h e m i c a l i s con- s i d e r e d t o be b i o d e g r a d a b l e and r e p o r t e d t o be t r e a t a b l e i n a s e c o n d a r y p l a n t . E t h y l e n e d i a m i n e , h e x y l e n e g l y c o l and c i t r a - z i n i c a c i d a r e a l s o c o n t a i n e d i n t h e d e v e l o p e r e f f l u e n t . c h e m i c a l s may n o t b e h i g h l y t o x i c , b u t i t a p p e a r s t h e y have a v e r y low b i o d e g r a d a b i l i t y i n a s e c o n d a r y t y p e t r e a t m e n t p l a n t . T h u s , t h e r e may b e some p e r s i s t e n c e o f t h e s e c h e m i c a l s i n t h e e n v i r o n m e n t . ,
1 i
These'
i i i
1 2 8
Goron i s t o x i c t o some a g r i c u l t u r a l p r o d u c t s a t c o n c e n t r a t i o n s above 1 m g / l . i n w a t e r i s g e n e r a l l y u n s a t i s f a c t o r y f o r c r o p s , e s p e c i a l l y i f u s e d f o r i r r i g a t i o n .
C o n c e n t r a t i o n s o f g r e a t e r t h a n 4 m g / l o f boron
Boron l e v e l s of 50 m g / l i t e r have been r e p o r t e d t o r e d u c e t h e e f f i c i e n c y of b i o l o g i c a l t r e a t m e n t s y s t e m s .
A c e t a t e ( f rom a c e t i c a c i d ) i s n o t c o n s i d e r e d t o be t o x i c t o f i s h . I t does e x e r t a h i g h oxygen d e m a n d , i f dumped i n t o a s t r e a m , b u t i s r e a d i l y t r e a t e d i n a s e c o n d a r y p l a n t .
B 1 e a ch e s
F e r r i c y a n i d e i n a w a s t e e f f l u e n t i s c o n v e r t e d t o f e r r o c y a n i d e by t h i o s u l f a t e and o t h e r c h e m i c a l s . . T h u s , o n l y f e r r o and n o t f e r r i c y a n i d e i s n o r m a l l y d i s c h a r g e d from p h o t o g r a p h i c p r o c e s s i n g p l a n t s .
F e r r o c y a n i d e i s n o n - b i o d e g r a d a b l e . Al though t h e compound i s n o t p a r t i c u l a r l y t o x i c , i t i s s l o w l y c o n v e r t e d t o t o x i c f r e e c y a n i d e i n t h e p r e s e n c e o f s u n l i g h t and a i r . Numerous r e p o r t s on t h e t o x i c e f f e c t s o f c y a n i d e s have been made. Some q u o t a t i o n s f o l l o w :
"The e f f l u e n t s f rom t r e a t m e n t p l a n t s r e - c e i v i n g p h o t o - w a s t e must b e d i l u t e d a t l e a s t 1 0 f o l d by r e c e i v i n g s t r e a m s t o s a t - i s f a c t o r i l y d i l u t e undegraded e f f l u e n t c y a n i d e s . (35)
"Under no c i r c u m s t a n c e s may t h e u n t r e a t - e d E A - 4 (Ektachrome) b l e a c h be s a f e l y r e l e a s e d i n t o any s t r e a m , f i e l d o p e r a t i o n s t h i s b l e a c h must b e dumped i n t o a h o l d i n g t a n k . . . . . I '
During m i l i t a r y
( 3 5 )
"An unknown amount o f i r o n c y a n i d e s and t h i o c y a n a t e s . ( l e s s t h a n 3 . 5 mg/l assuming good F l a n t pe r fo rmance ) w i l l b e p r e s e n t in t i l ( > C\ r ' < ? u c n t o f an Ektachrome w a s t e . . ,I , \ : - . , L ;!: l o r i n a t i o n and t h e a c t i o n 01: s~ii.i.i.:;ii; ;;;ay r e s u l t i n s u b s t a n t i a l c o n v e r s i o n o f t h e s e c h e m i c a l s t o h i g h l y t o x i c H C N and CNO- compounds. For t h e s e r e a s o n s , a t l e a s t a t e n f o l d d i l u t i o n of t h e t r e a t m e n t p l a n t e f f l u e n t i s n e c e s s a r y f o r any t r e a t m e n t p l a n t t h e e f f l u e n t of which r o u t i n e l y c o n t a i n s E A - 4 (Ektachrome p h o t o g r a p h i c ) w a s t e , A 1 0 0 f o l d d i l u t i o n i s p r e f e r a b l e . " (35)
, -
, ' *
129
"Dcpcnding o n y o u r l o c a l i t y and y o u r r e - g u l a t o r y a g c n c y , f e r r i c y a n i d e and f c r r o - c y a n i d e c f E l u e n t s may necd t i g h t c o n t r o l . T h e r e f o r c , r c g c n e r a t i o n o f f e r r i c y a n i d e - b e a r i n g b l c a c h e s , where p r a c t i c a l , i s r e c - oinmended, b o t h as a p o l l u t i o n - c o n t r o l measure and f o r economic r e a s o n . " (32 )
T h i o c y a n a t e s may a l s o b e f o u n d i n p h o t o g r a p h i c b l e a c h e s w i t h t h e s e r e s u l t i n g problems :
" T h i o c y a n a t e s a r e t o x i c i n c h r o n i c d o s e s a t r e l a t i v e l y low l e v e l s . T o x i c i t y i s r e l a t e d t o i n t e r f e r e n c e w i t h t h y r o i d f u n c t i o n . P l a n t s 'of t h e c a b b a g e - t u r n i p f a m i l y may b e a b l e t o c o n c e n t r a t e t h i o c y a n a t e s f rom i r r i - g a t i o n w a t e r . " ( 3 6 )
t o r e l ease amounts o f c y a n i d e t o x i c t o a c q u a t i c l i f e a t c o n c e n t r a t i o n s of 2 mg/l o r above" ( 3 6 )
. . . . . t h i o c y a n a t e s decompose i n s u n l i g h t I 1
F i x i n P Baths
S i l v e r i s a n o t h e r s e r i o u s p o l l u t a n t . I n c o n c e n t r a t i o n s a s low a s 0.005 m i l l i g r a m s p e r l i t e r , i t h a s a l e t h a l e f f e c t on b a c t e r i a n e c e s s a r y t o t h e d i g e s t i o n o f sewage. ( 3 0 ) Thus , e v e n minute t r a c e s o f s i l v e r i n t h e p h o t o g r a p h i c e f f l u e n t can b e h a r n f u l t o b i o l o g i c a l t r e a t m e n t p l a n t s o r t o s t r e a m l i f e . I t has b e e n s t a t e d t h a t s i l v e r w i l l p r e c i p i t a t e o u t as s i l v e r h a l i d e i n w a s t e e f f l u e 6 t s and b e removed i n w a s t e t r e a t m e n t p l a n t s . T h i s i s se ldom t r u e , b e c a u s e t h e t r a n s i t t ime from p h o t o g r a p h i c l a b - o r a t o r y t o sewage t r e a t m e n t p l a n t i s i n s u f f i c i e n t t o a l l o w p r e - c i p i t a t i o n t o o c c u r . S i l v e r goes i n t o t h e t r e a t m e n t p l a n t as a s i l v e r complex t h a t w i l l k i l l enough b a c t e r i a t o r e d u c e s i g n i f - i c a n t l y t h e e f f i c i e n c y o f a p l a n t .
Concern ing d i s c h a r g e t o a t r e a t m e n t p l a n t , Greenwel l (31 ) r e - p o r t e d " t h a t s i l v e r i n p h o t o g r a p h i c p r o c e s s i n g e f f l u e n t i s i n a complex f o r m and i s n o t t o x i c t o b i o l o g i c a l t r e a t m e n t sys tems" . However, t h a t d a t a was b a s e d upon a b i o l o g i c a l s y s t e m f o r t r e a t i n g p h o t o g r a p h i c w a s t e s o n l y . LeFebvre and C a l l a h a n r e p o r t e d t h a t s i l v e r d e s t r o y s a c t i v a t e d s l u d g e i n a m u n i c i p a l p l a n t a t v e r y low c o n c e n t r a t i o n s . ( 3 5 ) I t i s s a f e t o assume t h a t n o s i muni- c i p a l p l a n t s now r e c e i v e some s i l v e r and i t may b e a cause f o r r educed p l a n t e f f i c i e n c y . t h e p l a n t w i l l h ave s i g n i f i c a n t t o x i c e f f e c t on t h e a c q u a t i c o r - ganisms o f t h e t r e a t m e n t p l a n t r e c e i v i n g water .
S i l v e r i o n a l s o r e d u c e s B iochemica l Oxygen Demand r e s u l t s by p r e v e n t i n g t h e a c t i o n o f m i c r o o r g a n i s m s . A c o n c e n t r a t i o n of 0 . 0 3 mg/l s i l v e r p roduced a 2 5 % r e d u c t i o n i n BOD measurement , w h i l e a 1 . 0 mg/l c o n c e n t r a t i o n produced an 819 i n t e r f e r e n c e .
I n a d d i t i o n , a n y s i l v e r p a s s i n g t h r o u g h
( 3 0 )
130
1- 1 I ; i i o s ~ i l i n t c 211~1 s u l f i t c a r c n o t t i i r c c t l y t o x i c t o f i s h . ilow- c \ -L ' I ' , i:' i1:iiiipcti i n t o a l i i kc o r s t r c m , t h c s e chemica l s r o b o s y s c i i Lro:ii t h e w n t c r and "suffocate" n c q u a t i c l i i e . I n t h a t c a s e , ti:c chcni icn ls a r e i n d i r c c t l y t o x i c t o t h e a c q u a t i c l i f c . If duiiiped t o a i i iuii icipal p l a n t hav ing p r i m a r y and s e c o n d a r y t r ea t i i i c i i t , t h e s e c h e i i ~ i c a l s r e c e i v e a d e q u a t e t r e a t m e n t . IIowcver, t l i i o u s u l f a t e and s u l f i t e have h i g h c h l o r i n e demands. Thus, t h e y inay r o b t h e d i s i n f e c t a n t power o f c h l o r i n e , u s e d t o k i l l b a c t e r i a i n e f f l u e n t f rom t h e t r e a t m e n t g l a n t . Many p h o t o f i n i s h e r s a r e a f f e c t e d by c h l o r i n e demand laws.
Hendr i ckson and Durbin (34) have t h u s r e p o r t e d :
"The t h i o s u l f a t e i n t h e f i x i n g s o l u t i o n , even a f t e r t h e s i l v e r h a s been removed, a l s o c r e a t e s a problem i n t h e t r e a t m e n t p l a n t . I t i s a s t r o n g r e d u c i n g a g e n t which r e a c t s w i t h t h e d i s i n f e c t a n t u sed i n t h e p l a n t . \\'hen l a r g e q u a n t i t i e s o f f i x i n g s o l u t i o n a r e dumped, a s t h e y some- t i m e s a r e , t h e m u n i c i p a l p l a n t o p e r a t i o n i s u p s e t b e c a u s e t h e t h i o s u l f a t e h a s t a k e n a l l t h e c h l o r i n e n o r m a l l y used t o p u r i f y t h e w a s t e . I '
Ammonium i o n , c o n t a i n e d i n some f i x e r s , i s a n u t r i e n t f o r a l g a e . I f t h e pH i s t o o h i g h (>pH 8 ) , ammonium i o n forms ammonia. Ammonia i s a l s o used as an a g r i c u l t u r e f e r t i l i z e r and i s a common i n g r e d i e n t i n d o m e s t i c sewage . D i s p o s a l t h r o u g h t h e m u n i c i p a l w a s t e t r e a t m e n t p l a n t s h o u l d be e f f e c t i v e .
Some s p e c i f i c r e p o r t e d problems w i t h f i x e r s f o l l o w :
" D e s i l v e r e d EA Ektachrome ( p h o t o g r a p h i c ) w a s t e c a n n o t b e d i s p o s e d o f w i t h o u t de- g r a d a t i v e t r e a t m e n t u n l e s s such a c t i o n i s j u s t i f i e d as d e f i n e d i n E x e c u t i v e Or- d e r s 1 1 5 0 7 and 1 1 5 1 4 ( N a t i o n a l C r i s i s ) . When s o j u s t i f i e d , EA-4 w a s t e may b e i n t r o d u c e d u n t r e a t e d i n t o s t r e a m s w i t h a volume o f a t l e a s t 3.4 c u b i c f e e t p e r s e c o n d ( C F S ) . . . , I t ( 3 5 )
" D e s i l v e r i n g E A - 4 (Ektachrome) f i x e r b a t h p r i o r t o d i s p o s a l i s mandatory r e g a r d l e s s o f t h e d i s p o s a l t e c h n i q u e . N o n - d e s i l v e r e d waste i s e x t r e m e l y t o x i c t o a l l b i o l o g i c a l s y s t e m s t e s t e d . " (35 )
131
"(Ektacliroine) E A - 4 w a s t c m u s t b e d c s i l v e r - cd p r i o r t o s t r e a m d i s p o s a l . D i s p o s a l o f wastes c o n t a i n i n g s i l v e r c o n t e n t , cvcn f o r a s h o r t p e r i o d w i l l r e s u l t i n s e r i o u s p o l l u t i o n . " (35 )
"The e x t r e m e t o x i c i t y of n o n - d e s i l v e r e d E A - 4 (Ektachrome) w a s t e t o a c t i v a t e d s l u d g e o rgan i sms i s c a u s e d by t h e a c c u m u l a t i o n o f s i l v e r i n t h e s l u d g e . ' ' ( 3 5 )
" S i l v e r removal i s a mandatory r e q u i r e m e n t f o r p h o t o w a s t e b e i n g i n t r o d u c e d i n t o a b i o l o g i c a l t r e a t m e n t sys tem. ' ' ( 3 5 )
. , . , ( f i x ) d i s p o s a l p r e s e n t s a s e r i o u s p o l l u t i o n problem i n v iew o f t h e f a c t t h a t i n l a r g e s c a l e i n s t a l l a t i o n s t h e volume o f f i x i n g s o l u t i o n t o b e d i s c a r d - ed can b e v e r y l a r g e and f u r t h e r i n view o f t h e f a c t t h a t t h e t h i o s u l f a t e i o n which i s p r e s e n t i n t h e s o l u t i o n f o l l o w i n g r e c o v e r y o f t h e s i l v e r i s a ma jo r p o l l u t a n t b e c a u s e o f i t s h i g h oxygen demand."
f t
"A p h o t o g r a p h i c l a b o r a t o r y i n a modera t e s i z e d sewage s y s t e m would a l m o s t c e r t a i n - l y p o s e a c o n t i n u i n g t h r e a t t o a n a c t i v a t e d s l u d g e p l a n t o r t o sewage d i g e s t i o n ..." ( 3 6 )
"Sodium t h i o s u l f a t e s u s e d i n l a r g e q u a n t i t i e s i n p h o t o g r a p h i c p r o c e s s i n g i s a s t r o n g r e - duc ing a g e n t and c o u l d a c c e l e r a t e t h e r e - d u c t i o n o f f e r r i c y a n i d e - t o HCN." (36)
. . . . t h e l e t h a l c o n c e n t r a t i o n o f s i l v e r may be as low a s 0 . 0 0 5 mg/l f o r f i s h and 0 . 0 1 mg/l f o r b a c t e r i a s o t h a t e v e n minu te t r a c e s o f s i l v e r i n p h o t o g r a p h i c e f f l u e n t c o u l d b e h a r m f u l t o b i o l o g i c a l t r e a t m e n t p l a n t s or t o r i v e r l i f e . ' ' ( 3 0 )
II
N e u t r a l i z e r s
N e u t r a l i z e r s a r e u s u a l l y of l i t t l e c o n c e r n as p a r t o f a P h o t o g r a p h i c was te e f f l u e n t . A c e t a t e i s t h e p r i m a r y o r g a n i c c h e m i c a l and i t has b e e n d i s c u s s e d p r e v i o u s l y u n d e r S t o p B a t h s .
1 3 2
S t n b i l i z c r s
Zinc is t h c p r i m a r y contnr i i inant o f t h e stabiliscr. I t h a s been r e p o r t e d ( 3 0 ) as b e i n g t o x i c t o f i s h i n t h e r a n g c o f 1 - 2 i n g / l . T h e c r i t i c a l l e v e l in raw sewage , f o r continuous doses on b i o l o g i c a l sys tc ins , i s 5 - 1 0 mgjl. ( 3 0 ) . The c r i t i c a l l e v c l i n raw sewage f o r a f o u r - h o u r shock d o s e , g i v i n g a s i g n i f i c a n t r e d u c t i o n in a e r o b i c t r e a t m e n t , i s 160 mg/l; w h i l e t h e maximum c o n c e n t r a t i o n o f z i n c p t h a t w o u l d n o t i m p a i r a n a e r o b i c d i g e s t i o n Q$ prilnary and s e a m d a y zreatment i a n t s l u d g e s t i s 10 mg/l . ( 3 0 ) Zinc i ~ f i w i i l a l s o i n t e r f e r e with I? !i d d i e m i e a l O X Y ~ E A Dejjafid (BOD) measurements . T e b b u t s ( 3 0 ) r e p o r t s t h a t a c o n c e n t r a t i o n of 1 mg/l r e d u c e s BOD measurement by 8 % , w h i l e a 7 . 0 mg/lpconcen- t r a t i o n p r o d u c e d a 2 5 % i n t e r f e r e n c e ,
133
P r e h a r d c nc r
Neutralizer
1st Developer
1st stop
1st Wash
C o l o r Developer
2nd Stop and Hardener
2nd Wash
Bleach
F i x
3rd Wash
Stabilizer
c
134
a E 0 Ll
t-i
I w Q) k 3 M
. I 4
c4
S T E P S . IN COLOR PROCESS
The c o m p o s i t i o n o f t h e s o l u t i o n s u s e d i n t h e c o l o r p r o c e s s a r e shown i n Tab le E - 2 . The f u n c t i o n of each s o l u t i o n i s as f o l l o w s :
a . P r e h a r d e n e r - Reduces e m u l s i o n s w e l l i n g d u r i n g p r o c e s s i n g ,
b , N o u t r a l i a r - Neutralizes h a r d e n i n g a g e n t s carr ied over by t h e f i l m t o p r e v e n t t h e i r r e a c t i o n w i t h t h e c o u p l i n g a g e n t s i n t h e f i l m .
c. F i r s t Developer - Exposed a r e a s a r e d e v e l o p e d t o g i v e a b l a c k - a n d - w h i t e n e g a t i v e s i l v e r image.
F i r s t S t o p Bath - S t o p s a c t i o n of F i r s t Developer and r e - duces emul s ion s w e l l .
d .
e . Water Wash - F l u s h e s a c i d s o l u t i o n o f f o f t h e f i l m .
f . C o l o r Developer - Develops a l l r e m a i n i n g s i l v e r h a l i d e , r e s u l t i n g i n p o s i t i v e images .
g . Second S t o p Bath - S t o p s a c t i o n o f t h e C o l o r Deve lope r .
h . Water Nash - F l u s h e s t h e a c i d s o l u t i o n o f f o f t h e f i l m .
i. Bleach - A l l m e t a l l i c s i l v e r i s c o n v e r t e d t o s i l v e r h a l i d e .
j ,; F i x i n g Bath - S i l v e r h a l i d e s a r e removed by r e a c t i o n w i t h t h i o s u l f a t e .
k. Water Wash - F i x i n g b a t h f l u s h e d o f f o f f i l m
1. S t a b i l i z i n g Bath - Hardens e m u l s i o n and s t a b i l i z e s P y e image.
135
w
d c;1 5l a
C b a c! M h
c, d cd v)
I I
n
i
I
l
I
0 r(
.- .
TABLE E - 2
(Cont inuecl)
_ -
__ - - __ - - CONCENTRATION IW I J j>! G R h l l S PER LITI ’R TYPE OF SOLUTION -
- __ - AND pH R A N G E 1 0 t o 100 1 t o 16 LESSTIAN 1 __ -.__
S t o p B a t h s S u l f a t e Aluminum pH 2 t o 4 A c e t a t e B o r a t e
C i t r a t e - - - _ - _
F e r r i cy a n i d e F e r r i c y a n i d e B i c a r b o n a t e B l e a c h e s F e r r o c y a n i d e N i t r a t e
P
-.I w pH 5 t o 8
F i x i n g B a t h s C h l o r i d e pH 4 t o 8 T h i o s u l f a t e
Ammonium
Aluminum B i s u l f i t e B i c a r b o n a t e B o r a t e A c e t a t e Bromide S i l v e r t h i o s u l f a t e complex F e r r o c y a n i d e Formal i n Se qu e s t e r i ng a g c i i t
TABLE E - 2
(continued)
TYPE OF 1 'il'ION CONCENTRATION RANGE IN GRANS PER LITER LESS THAN 1 A N D pIl - 4 1 to 10
Neutrali PH 5
Bromide Sulfate Hydroxy 1 ami ne
Acetate
S t a b i l i I L : pH 7 to 9 Formaldehyde
Zinc Sulfate Phosphate Citrate Benzoate Sequestering agent
We t t i n g agent
___
T A B L E E - 3
APPROXIMATE C I I M I C A L CONCEN’TIb lTIONS IN
EFFLUENTS FRObl P1101’0 PROCESSING bIACII IXES
(mg/ l u n l e s s o t h e r w i s e n o t e d )
1 2 3 4 5 6 7 8 9
E k t a - E k t a - B/W B / N B/;$ c- 2 2 P r i n t - C E - 4 P r i n t - R F i l m P a p e r ME-4 E C O - 2 Revers: : l
Aluminum I o n Ammon i um I o n
h - ~ H o r 3 x UJ Bromide I o n w
C a r b o n a t e I o n F e r r o c y a n i d e N i t r a t e I o n P h o s p h a t e I o n S u l f a t e I o n S u l f i t e I o n T h i o c y a n a t e I o n Thiosulfate I o n Zinc I o n Chromium ( + 6 ) A c e t a t e I o n B e n z y l A l c o h o l C o l o r D e v e l o p e r C D - 3 E l o n Fo r ma 1 de h y d e Hydroqu inone Mydroxy l Amine S u l f a t e
Volume ( l / m i n )
BOD
70 670 1 8 0
90 1 4 0 240
190
2 2 0
800 1 2 0 1 2 0
3 30
70
820
20 80
3 0 0 60
310 160 3 1 0
1 3 0 210
1 0 0 0 30
140 1 6 0
50
360
4 0
30
1 2 4 0
40 1 0 90
110 290
1 2 0 2 0 0 300
1 0 1 2 0
250 2 0 60 40 60 60 2 0
30
380
1 0 1 0
20 1 0 50 70 20 2 1 0 70
4 0 60 5 0
1 0 0 130 . 2 2 0
1 6 0 130 710 10
170 3 2 0 160 80 20 1 0
190 50 1 0 20 I 10 30
60 20 30
4 30 240 4 7 0
2 5 0 1 0
4 0 0 9 1 0
1 1 1 0
8 5 0 1 3 8 0 2140
50 800
1 8 7 0 1 9 0 4 3 0
440 39 0 1 9 0
2 0
2570
260 3 0 1 0
4 0 0 600 1 3 0 1110
810 2600 30 1300 1 6 0
810 4 8 0 70
2 0 1920 2 2 0
2 30 2 1 0
4 6 0 10 1 9 0 2 0 1 9 0
7 0 30
2 2 7 0 3 5 0
n k 0
r-4 0 U (d d h
F1
k 0 rl 0 U .d M 7 P-4
e
n
k 0 r(
0 U (d cei M G
k 0 l-4 0
n
r: U
-3 0
L 4 v
e, > *d c, rd M e, 2
k 0 d 0 U
r(
n c, d 3 3:
U
c, F: *d k G cj c, jc w
I
v
k a, G cd PI
k 0 ri 0 U
N
m
I d
w 0 E 0 k rc U rd c, & w v
m 0 7j .ri ri m ri cj vr k 0 > 0 d
k 0
l-4 0 U
M
n p: I
c, c
.r(
k !a (d c,
w v
k 0 c4 cj k
d cj m k 0 > r 3 p: k 0
l-4 0 U
-3-
n (v
0 U w
I
2 0 k s: U cd c, 24 w v, v, a, V 0 k 14 v
E l-4 .rl c4
e, .d > 0
ri (d v) k 0 > 0 d k 0 rl 0 U
Q)
1 4 0
T A D L E E - 4
B io ihcn1 ica l O s y g c n Dcmand o f Chemicals Uscd in
Pliorogi'npliic Processing Compared t o Theoretical Oxygen Demand (From Pamphlet J-28)
Kodnk Anti-Calcium No. 3 Kodak Anti-Fog No. 1 Kodak Anti-Fog No. G Kodak Anti-FoE No. 7 Balancing Developing Agent BD- 82
BD- 86 BD- 89
Benzyl A l c o h o l B u t ane d i on e Carbowax 1,540 Carbowax 4000 Citrazinic Acid Citric Acid, bfonohydrate Color Developing Agent CD-1
CD- 2 CD- 3 CD- 4 CD- 5
Coupling Agent C-16 bl- 40 y - 5 4
Dicolanine Elon Developing Agent Ethylene Diamine Formalin Formic Acid Glacial Acetic Acid Hardening Agent -HA-2 Hardening Agent -HA-1 Hexylene G l y c o l Hydroquinone Methelon Developing Agent Phenidone Kodak Potassium Ferricyanide Revers a1 Agent RA- 1 Sodium Acetate Sodium Bisulfate Sodium Citrate (2H20) Sodium Ferrocyanide, Decahydrate Sodium Formate Sodium Isoascorbate Sodium Sulfite Sodium Thiosulfate ( 5 H 2 0 ) Stabilizing Agent-SA-1 Sodium Thiocyanate
Tlieor c t i ca 1 Oxygen Demand TOD (ultimate) -5 BOD
it
0 . 9 0 2 . 9 8 2 . 1 5 2.70 1 . 1 3 1 . 9 1 2 . 7 0 2 . 5 5 1 . 6 8 3 . 5 9 3 . 6 2 1 . 3 6 0 . 6 8 2 . 5 3 2 . 6 8 1 . 5 8 1 . 9 1 2 . 2 8 2 .47 1 . 4 4 2 . 2 0 1 . 9 6 1 . 8 6 3 . 4 7 0 . 6 2 0 . 2 3 1 . 0 6 2 .22 0 . 6 0 2 . 3 1 . 9 1 . 9 8 2 .67 1 . 5 2 3 . 5 0 0 . 7 8 0 . 1 6 0 . 4 9 1 . 0 6 0 . 2 4 1 . 2 5 0 . 1 2 0 . 3 2 1 . 5 4 1 . 5 8
A
0 . 0 0 3 0 . 0 4 0.05 0 . 0 3 0.07 0 . 1 4 0 . 1 7 1 . 8 0 0 . 5 5 0 . 0 3 0 . 0 2 0 . 0 0 3 0.4 Oil3 0 . 1 4 0.10 0.13 0 . 0 8 0 . 0 3 0 . 0 3 0 . 0 3 0 . 1 5 0 .70 0 . 0 3 0 . 3 7 0 . 0 2 0 .74 0 . 0 7 0 . 0 1 0 . 0 0 3 1.1 0 . 1 6 0.16 0 . 0 0 3 0 . 0 3 0 . 5 8 0 . 1 6 0 . 3 5 0 . 0 0 3 0 . 0 1 6 0 . 2 9 0 . 1 2 0 . 2 0 . 0 3 0 . 0 3
BODS ?'OD ~
x 100
0 . 3 3 1 . 3 4 1 . 4 0 1.11 5 . 3 7 . 3 6 . 3
6 6 . 3 3 3 . 3 ' 0 . 8 4 0 . 5 5 0 . 2 2
5 . 1 5 5 . 6 0 6 . 3 3 6 . 8 3 . 5 1 . 2 2 . 1 1 . 3 7 7 . 6 5
5 9 . 0
3 7 . 6
5 9 . 5 9 . 1
6 8 . 0 3 . 6 1 . 6 7 0 . 1 3
58.0 8 . 1 6 . 0 0 .20 0 . S 6
. 8 6 5
7 3 . 5 1 0 0 . 0
6 5 . 0 0 . 2 8 8.0
2 3 . 2 1 0 0 . 0
6 2 . 5 1 . 9 5 1 . 9 0
* Unit weight of oxygen demand per unit weight of chemical (i.e gm OZ/gm)
161
TABLE E - 5
RELATIVE INEFFECTIVENESS OF BIOLOGICAL
TYPE OF TREATMENT OF PHOTOGRAPHIC CHEMICALS
P e r c e n t Range
0 . 0 - 0 . !I !.I
1.9 - 9.99
10.0 - 4 9 . 9
5 0 . 0 - 8 9 . 9
9 0 . 0 - 1 0 0
Number o f Chemicals in P e r c e n t of Each C a t e g o r y T o t a l
9
2 3
3
8
2
5 1 . 2
6 . 7
1 7 . 7
4.4
45 100.0
142
r-. i : - c a t ; ? e n t o f P h o t o g r a p h i c Waste O u t s i d e o f P r o c e s s i n g P l a n t ~
T h e f o l l o w i n g s e c t i o n was e x t r a c t e d i n i t s e n t i r e t y f r o m Pamphlet J-ZS, " D i s p o s a l o f P h o t o g r a p h i c Wastes" by Eastman Kodak Co. unde r t h e s e c t i o n e n t i t l e d : Methods o f Waste T r e a t m e n t ,
IIStorm s e w e r s o r su r f ace d r a i n a g e f o r d i s - c h a r g i n g p r o c e s s i n g e f f l u e n t s w i t h o u t t r e a t - ment s h o u l d n o t b e u s e d b e c a u s e o f t h e l i k e l i h o o d o f v i o l a t i n g t h e s t ream s t a n d - a r d i n t o which t h e sewer w a s t e f l o w s . ' t
" S e p t i c t a n k s a r e b i o l o g i c a l s y s t e m s b u t a r e n o t recommended f o r d i s p o s a l of p h o t o - g r a p h i c p r o c e s s i n g w a s t e s . S e p t i c t a n k s do n o t d e g r a d e t h e wastes s u f f i c i e n t l y , a r e g e n e r a l l y d e s i g n e d f o r sma l l e r volumes , p roduce t o x i c and odorous p r o d u c t s , can - n o t be i n s t a l l e d i n a l l l o c a t i o n s , and r u n t h e r i s k o f c o n t a m i n a t i n g ground w a t e r s . S e p t i c t a n k s a r e a n e r o b i c systems, t h a t i s , t h e b i o l o g i c a l p r o c e s s p r o c e e d s w i t h o u t a i r , ' I
"An a e r a t e d l agoon i s n o t a p r a c t i c a l s o l u t i o n f o r many p r o c e s s o r s b e c a u s e a l a r g e a r e a o f l a n d i s r e q u i r e d . I t i s a l s o a s a f e t y h a z a r d and r u n s t h e r i s k o f i n c o m p l e t e d e g r a d a t i o n , t h e c r e a t i o n o f o d o r s , and c o n t a m i n a t i o n o f ground w a t e r s . However, i f t h e l a g o o n i s l a r g e enough, i s a e r a t e d , a n d h a s an imperv ious l i n e r , i t may b e s a t i s f a c t o r y . The o v e r f l o w s h o u l d b e checked t o i n s u r e t h a t i t d o e s n o t ' c o n t a m i n a t e t he s t r e a m i n t o which i t f l o w s . "
"Deep-well i n j e c t i o n i s l e g a l i n some s t a t e s , b u t o n l y a f t e r c a r e f u l s t u d y h a s been made t o p rove t h a t t h e r o c k s t r u c - t u r e o f t h e a r e a i s s u c h t h a t t h e r e i s no p r o b a b i l i t y o f c o n t a m i n a t i n g ground w a t e r s . The re i s a lways t h e i n h e r e n t dange r o f c o n t a m i n a t i o n o f g r o u n d w a t e r s . Fu r the rmore , t h e c o s t o f i n v e s t i g a t i n g , l e t a l o n e c o s t of d r i l l i n g a n d o p e r a t i n g t h e w e l l , i s e x t r e m e l y h i g h . However, Bea le A i r Force Base i n C a l i f o r n i a has t h r e e i n j e c t i o n w e l l s f o r i t s p h o t o g r a p h i c p r o c e s s i n g w a s t e s . "
143
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" O I L til'\ b , ~ > is o i O L I ? * L \ ~ ! ) L \ i.i.iiic1ltill. wosk, we rcconiuic1lJ t r c , i t i n g processing effluents i n ail a c r o b i c . b i o l o g i c a l w a s t e t r e a t m e n t p l a n t . s y s t c m d c s t r o y s m o s t oxygen demanding chem- i c a l s comiiion t o p h o t o g r a p h i c p r o c e s s i n g e f f l u e n t s j u s t a s i t d e s t r o y s d o m e s t i c s a n i t a r y w a s t e s . The p l a n t i s somet imes r e f e r r e d t o a s a s e c o n d a r y p l a n t , t h e p r i m a r y p l a n t b e i n g f o r t h e p u r p o s e o f o n l y s e p a r a t i n g s o l i d s f rom t h e w a s t e . Laws a r e b e i n g f o r m u l a t e d o r a r e a l r e a d y i n e f f e c t i n v i r t u a l l y a l l s t a t e s i n t h e U n i t e d S t a t e s t o r e q u i r e t h e e q u i v a l e n t o f s e c o n d a r y t r e a t m e n t of a l l w a s t e s e n t e r i n g a s t r e a m o r l a k e . A b i o l o g i c a l t r e a t m e n t p l a n t makes u s e o f t h e same t y p e o f a e r o b i c b i o l o g i c a l a c t i v i t y t h a t would o c c u r i f t h e w a s t e were t o f l o w down a s t r e a m , e x c e p t t h a t t h e w a s t e s a r e d e g r a d e d i n a t r e a t m e n t p l a n t i n a m a t t e r o f h o u r s , r a t h e r t h a n t h e days t h a t a r e r e q u i r e d i n s t r e a m s . i n s u r e s r a p i d a e r o b i c d e g r a d a t i o n i n a w a s t e - t r e a t m e n t p l a n t . "
"One t y p e o f s e c o n d a r y sys t em i s c a l l e d a t r i c k l i n g f i l t e r , s o named b e c a u s e t h e a e r a t e d w a s t e t r i c k l e s o v e r a l a r g e s u r f a c e o f s m a l l r o c k s o r p l a s t i c s o t h a t t h e d e - s i r e d b i o l o g i c a l d e g r a d a t i o n i s accompl i shed . "
"Another common t y p e o f s e c o n d a r y p l a n t i s t h e a c t i v a t e d - s l u d g e p l a n t , u s u a l l y b u i l t i n l o n g r e c t a n g u l a r t a n k s . I t u t i l i z e d b i o l o g i c a l a c t i o n b r o u g h t a b o u t by a i r , b a c t e r i a and n u t r i e n t s . Some o f t h e d e - g r a d a t i o n p r o d u c t s a r e removed a s g a s e s , some r e m a i n d i s s o l v e d , and some p r e c i p i t a t e a s a s l u d g e . M u n i c i p a l t r e a t m e n t p l a n t s d r y t h e s l u d g e and g e n e r a l l y u s e i t f o r l a n d - f i l l . More comple t e b i o l o g i c a l de - g r a d a t i o n may be a t t a i n e d by r e c i r c u l a t i n g some o f t h e s l u d g e and e x t e n d i n g t h e a e r a t i o n t i m e . O r g a n i c compounds, i f d e g r a d e d com- p l e t e l y w i l l p r o d u c e c a r b o n d i o x i d e , w a t e r and o t h e r p r o d u c t s . P r o c e s s i n g c h e m i c a l s s u c h a s hypo a r e a l s o d e g r a d e d by t h e b i o l o g i c a l p r o c e s s . "
The b i o l o g i c a l d e g r a d a t i o n i n t h e
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I 1 . j > ' L i ~ c b i o l o g i c a l t r c ; ~ t i n e i l t p l a n t i s t h e
litns t C x p c n s i v c nicthocl known Cor des t r u c - t i o i i o i mixed osygcn-demanding w a s t e s , m o s t o f which a r e o r g a n i c . P r o p e r o p e r - a t i o n of a p l a n t r e q u i r e s c a r e f u l a t t e n - t i o n . The l a r g e m u n i c i p a l p l a n t s c a n o p e r a t e a t much lower c o s t p e r u n i t amount o f w a s t e t h a n s m a l l p l a n t s . I t i s p r o b a b l y l e s s e x p e n s i v e t o pay a muni- c i p a l i t y t o h a n d l e t h e w a s t e f rom a p r o c e s s i n g l a b o r a t o r y compared w i t h con- s t r u c t i n g and o p e r a t i n g one f o r t h e e x c l u s - i v e u s e of t h e l a b o r a t o r y . "
I n - P l a n t T rea tmen t v i a Recovery and R e c i r c u l a t i o n o f P o t e n t i a l l y T o x i c Ivaste M a t e r i a l s .
I n - p l a n t t r e a t m e n t o f p r o c e s s w a s t e s a p p e a r s t o b e t h e b x s t method o f r e d u c i n g p o l l u t i o n o f c h e m i c a l s ' t h a t :
- c a n n o t b e t r e a t e d i n common t r e a t m e n t p l a n t s ( n o n - b i o d e g r a d e a b l e s h a v i n g a BOD5 l e s s t h a n 10% of t h e i r T O D : (See T a b l e E - 4 ) and
- a d v e r s e l y a f f e c t t h e t r e a t m e n t method ( f o r b i o l o g i c a l p l a n t s : t h i o s u l f a t e , i r o n , b o r o n , s i l v e r , z i n c and t h i o c y a n a t e ) .
S i l v e r Recovery and F i x e r Reuse
The p r o f i t a b i l i t y o f s i l v e r r e c o v e r y from f i x i n g b a t h s i n p r o - c e s s i n g p l a n t s h a s b e e n w e l l known f o r many y e a r s . economic c o n s i d e r a t i o n s a r e t h e s u b s t a n t i a l r e t u r n f o r t h e r e - c o v e r e d s i l v e r , a n d c h e m i c a l s a v i n g s t h a t a r e p o s s i b l e by u s i n g l e s s f i x e r . P o l l u t i o n aba temen t b e n e f i t s a l s o r e s u l t , i n t h a t l e s s s i l v e r and l e s s f i x a r e sewered .
The pr ime
By m a i n t a i n i n g low amounts o f s i l v e r i n t h e f i x i n g b a t h , t h e f i l m f i x e s e a s i e r and more c o m p l e t e l y , and t h e s u b s e q u e n t wash s t e p becomes more e f f i c i e n t . t h a t i s d i s c a r d e d w i t h a r e c o v e r y s y s t e m p l u s t h e r e d u c e d amount of s i l v e r i n t h i s w a s t e s o l u t i o n i s c o n s i s t e n t w i t h i n d u s t r y \ s e f f o r t t o r e d u c e p o l l u t i o n . f i x e r i s r e u s e d , . t h e t o t a l volume o f s o l u t i o n i s r e d u c e d con- s i d e r a b l y , t h u s p e r m i t t i n g l e s s f r e q u e n t mixing a n d / o r p o s s i b i l i t y of smaller s t o r a g e t a n k s .
The lower amount o f w a s t e f i x e r
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I n f i x i n g b a t h s , sodium t h i o s u l f a t e (hypo) i s u s e d t o f i x t h e image
- - Ag+ f S 2 Q 3 + (Ag S z O j ) - s o l u b l e
by c o n v e r t i n g t h e undeve loped , i n s o l u b l e , s i l v e r h a l i d e t o a s o l u b l e complex ( s e e e q u a t i o n 4 7 ) . T h i s s o l u b l e complex d i f - fuses o u t o f t h e p h o t o g r a p h i c e m u l s i o n i n t o t h e f i x i n g b a t h . A s t h e f i x i n g b a t h i s u s e d , i t becomes a v e r y complex m i x t u r e . I n a d d i t i o n t o t h e o r i g i n a l components o f t h e f i x i n g b a t h , a u s e d b a t h c o n t a i n s : s o d i u m f e r r o c y a n i d e , sodium s u l f a t e , sodium b romide , g e l a t i n e , complex s i l v e r s a l t s , and v a r y i n g amounts of p r a c t i c a l l y a l l o f t h e c h e m i c a l s u s e d i n p r o c e s s i n g t h e m a t e r i a l . T h e r e f o r e , any method o f r e c o v e r y h a s t o make a l l o w a n c e s f o r t h e s e i n t e r f e r i n g s u b s t a n c e s . F o r t u n a t e l y , s i l v e r i s f a r r e - moved, in t h e e l e c t r o m o t i v e s e r i e s , f r o m any o t h e r m e t a l l i c r a d i c a l i n t h e s o l u t i o n . Most r e c o v e r y methods t a k e advan tage of t h e n o b l e n a t u r e o f s i l v e r .
B a s i c a l l y , t h e r e a r e two methods o f s i l v e r r e c o v e r y : chemica l and e l e c t r o l y t i c . The c h e m i c a l methods i n c l u d e p r e c i p i l a t i o n , m e t a l - l i c r e p l a c e m e n t , and i o n exchange t e c h n i q u e s . The e l e c t r o l y t i c methods. a r e more common i n p r e s e n t p r o c e s s i n g p l a n t s , b e c a u s e t h e y a r e c l e a n e r , u s u a l l y r e q u i r e l e s s o p e r a t i n g l a b o r , and p e r m i t t h e r e u s e of t h e f i x i n g b a t h a f t e r d e s i l v e r i n g , w i t h p r o p e r c h e m i c a l a d d i t i o n s . The f o l l o w i n g f a c t o r s a f f e c t t h e p u r i t y o f s o l u t i o n s t o be r e u s e d and t h e p u r i t y o f s i l v e r c o l l e c t e d :
1. A g i t a t i o n : A g i t a t i o n i s r e q u i r e d s o t h a t new, s i l v e r l a d e n s o l u t i o n i s a lways i n c o n r a c t w i t h t h e c a t h o d e s . I n s u f f i c i e n t a g i t a t i o n r e s u l t s i n a b l a c k e n e d o r s u l f i d e d d e p o s i t on t h e c a t h o d e s . A b a d l y s u l f i d e d d e p o s i t f o u l s t h e c a t h o d e s and r e s u l t s i n a s o f t d e p o s i t , t h a t may d r o p o f f and b e l o s t i n t h e r e c o v e r y c e l l .
S o l u t i o n pH: e n t , b u t pH changes i n t h e r a n g e 7 . 0 t o 1 0 . 0 have l i t t l e e f f e c t . I n a n a c i d s o l u t i o n , t h e p l a t e d s i l v e r t e n d s t o b e w h i t e even though t h e e f f i c i e n c y i s low. T h i s i s due t o t h e f a c t t h a t t h e s u l f i d e p roduced goes o u t o f s o l u t i o n i n t h e form o f hydrogen s u l f i d e g a s . I n a l k a l i n e s o l u t i o n s , t h e p l a t e d s i l v e r s u l f i d e s e a s i l y , y e t a s l i g h t l y darkened s i l v e r p l a t e may s t i l l p roduce a h i g h c u r r e n t e f f i c i e n c y . A t a pH o f 1 2 , t h e p l a t e d s i l v e r t u r n s brown ( s u l f i d e s ) a t any v o l t a g e .
t o produce a smooth s i l v e r d e p o s i t on t h e c a t h o d e s . e l e c t r o l y t i c a l l y n e u t r a l p a r t i c l e c a n be o c c l u d e d i n t h e
. s i l v e r a s i t d e p o s i t s on t h e c a t h o d e . When t h i s o c c u r s , t h e s i l v e r d e p o s i t w i l l fo rm o v e r t h e p a r t i c l e , p r o d u c i n g a s p o t
2 . Acid and a l k a l i n e f i x i n g b a t h s a r e q u i t e d i f f e r -
3 . S o l u t i o n F i l t r a t i o n : The s i l v e r b e a r i n g s o l u t i o n i s f i l t e r e d An
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oLr slia-i.11 c u r v n t u r c . C u r r c n t d e n s i t y w i l l b e h i g h e r a t t h i s v o i n t : f i - i . s t , c a u s i n g s i l v e r t o d e p o s i t f a s t e r a t t h e p o i n t t h n n on the r c s t ' o f t h e c a t h o d e and E i n a l l y , i n i t i a t i n g t h e s u l f i d i n g a c t i o n which f o u l s t h e p l a t e .
C u r r e n t Density: The maximum c u r r e n t d e n s i t y depends on a g i t a t i o n . 'Che i n d e p e n d e n t v a r i a b l e i s v o l t a g e . I f t h e v o l t a g e i s k e p t above a minimum a l l o w a b l e , v a l u e , an i n c r e a s e i n a g i t a t i o n may be 'used t o o b t a i n a h i g h e r c u r r e n t d e n s i t y .
E l e c t r o d e s : The m a t e r i a l u s e d i n t h e c o n s t r u c t i o n o f t h e e l e c t r o d e s i s i m p o r t a n t . G r a p h i t e i s u s u a l l y u s e d f o r t h e anode because i t i s r e s i s t a n t t o c o r r o s i o n and i t s e l e c t r i c a l r e s i s t a n c e i s low. S t a i n l e s s s t e e l i s t h e common c a t h o d e m a t e r i a l .
C o n t r o l o f S i l v e r C o n c e n t r a t i o n : The s o l u t i o n from which s i l v e r i s b e i n c r e c o v e r e d must c o n t a i n n o t l e s s t h a n 0 . 5 grams p e r l i t e r o f s i l v e r . I f t h e c o n c e n t r a t i o n i s l e s s t h a n t h i s , s i l v e r s u l f i d e w i l l fo rm i n t h e c e l l . S i l v e r s u l f i d e i s a b l a c k , f i n e l y d i v i d e d m a t e r i a 1 , w h i c h w i l l a ccumula t e on t h e c a t h o d e and f o u l i t . I f i t i s n o t con- t r o l l e d , t h e s u l f i d e w i l l p r e c i p i t a t e f rom t h e s o l u t i o n . I n a n a c i d s o l u t i o n , hydrogen s u l f i d e gas w i l l f o rm. The gas h a s an obnoxious odor ( r o t t o n e g g s ) and i s t o x i c . I f i t i s p r e s e n t , i t must b e removed by a d e q u a t e v e n t i l a t i o n .
r e c i r c u l a t i o n o f f i x e r can r e d u c e t h e c h l o r i n e demand d i s - c h a r g e f r o ~ i l 6 ~ h o t o g r a ~ h i c l a b by a s much a s 9 0 % , w h i l e r e d u c i n g che 20D5 f ~ c : : : o O - G C , : . a p p e a r zo ' : < . :::,: :.:!I-.- : ~ . ~ t h o d s t h a t a l l o w t h i s r e d u c t i o n . t o t a k e p l a c e . C~; , - : - . . LG~:S r c c i ~ c u l a t i o n of f i x e r s a l s o i n c r e a s e s i l v e r r e c o v e r y e f f i c i e n c y from a b o u t a 7 0 % maximum t o a 9 5 % maximum.
E l e c t r o l y t i c methods o f s i l v e r removal
B leach Recovery and Reuse
The b l e a c h i n g r e a c t i o n i n the p h o t o g r a p h i c p r o c e s s i s :
Overf low b l e a c h s o l u t i o n i s t h e n t r e a t e d s o as t o o x i d i z e f e r r o - c y a n i d e t o f e r r i c y a n i d e , t h e consumed h a l i d e i s added and t h e c h e m i c a l c o n c e n t r a t i o n s a d j u s t e d t o t h e d e s i r e d r e p l e n i s h e r t a n k l e v e l .
The m o s t common t e c h n i q u e o f b l e a c h r e g e n e r a t i o n i s t h e u s e of p o t a s s i u m p e r s u l f a t e . The r e a c t i o n i s :
P e r s u l f a t e r e g e n e r a t i o n i s w e l l documented.(38)
- - - - * 2 Fe(CN)6 - 3 + 2 so4
+ '2'8 -4
6 2 Fe (CN)
T h i s method has r e c e i v e d wide a t t e n t i o n b e c a u s e i t i s c h e a p , s i m p l e t o u s e , and does n o t r e q u i r e ma jo r c a p i t a l e x p e n d i t u r e s .
147
H O L C C V C ~ , t i ic a d d i t i o n o f s u l c a t e i n c r c a s e s t h e s p c c i f i c g r a v i t y 0 ; t h e 'oleacli,\vliicli u l t i n i a t c l y a f f e c t s b l e a c h i n g a c t i o n , A t t h a t p o i n t , t h e b l e a c h ' m u s t b c d i s c a r d e d i n l a r g e volumes, i m - p o s i n g a v e r y s e r i o u s p o l l u t i o n problem,
I i e g e n e r a t i o n , v i a o z o n a t i o n o r e l e c t r o l y s i s , p r o d u c e s no contam- i n a n t b y - p r o d u c t s and t h u s , t l i e r c would b e no need t o d i sGharge any b l e a c h . I t would b e c o n t i n u o u s l y r e c i r c u l a t e d . T h i s l a t e r iiietliod a l l o w s f o r 9 5 % r e d u c t i o n s o f complex c y a n i d e s d i s c h a r g e d t o t h e env i ronmen t .
O t h e r i n p l a n t r e c o v e r i e s have n o t been f o u n d s a t i s f a c t o r y f o r t h e p h o t o g r a p h i c p r o c e s s i n g i n d u s t r y , due t o p o t e n t i a l con tamin- a t i o n , q u a l i t y c o n t r o l , e t c . The c o n c e n t r a t i o n s o f t h e c h e m i c a l s found i n t h e w a s t e e f f l u e n t o f a t y p i c a l p h o t o f i n i s h i n g p l a n t a r e shown i n Table F - 1 , page 1 4 9 .
Tab le F - 2 l i s t s t h e amounts o f c h e m i c a l s , i n pounds p e r d a y , t h a t a r e d i s c h a r g e d by a t y p i c a l p h o t o f i n i s h e r p r o c e s s i n g Ektachrome, Kodacolor and E k t a c o l o r p r o d u c t s . A l s o l i s t e d i n T a b l e F - 2 , a r e t h e amounts of t h e same c h e m i c a l s t h a t a r e d i s c h a r g e d a f t e r t h e i n s t a l l a t i o n o f an i n - p l a n t t r e a t m e n t s y s t e m . The s y s t e m i n - c l u d e s e l e c t r o l y t i c s i l v e r r e c o v e r y , ozone r e g e n e r a t i o n o f f e r r i - c y a n i d e b l e a c h and ozone waste t reatment .
TABLE 17-1
C O N C E N T R A T I O N OF ClIEbl ICALS IN INUUSTRIAL WASTES
EFFLUENT AT A T Y P I C A L PHOTOFINISHING PLANT
Aminonium I o n Borax as B O 7 Bromide IoA C a r b o n a t e F e r r o c y a n a t e
N i t r a t e P h o s p h a t e S u l f a t e
. S u l f i t e S i l v e r
T h i o s u l f a t e T h i o c y a n a t e Z i n c A c e t a t e B e n z y i A l c o l h o
C o l o r D e v e l o p e r C D - 3 Formaldehyde Hydroquinone E l o n Hydroxylamine s u l f a t e
TOTAL MIXED EFFLUENT
(mg/ 1)
50 268 70
145 120
140 15 75
1 4 0 3
5 0 0 1 8
4 0 0 100
5 7 2 6 0
1 0 11 1 7
Sodium C i t r a t e 59
gpm ( p e a k l o a d ) 120
BOD5 ( a v e r a g e - n o m i x i n g ) 695 F l o w Rate l / m i n (peak l o a d ) 450
DILUTE WASH WATER O N L Y
(mg/l)
1 5 1 1 1
1
1 1
-
-
4 4
4 1
-
3 - - - 1
7 - 1 0 4 1 5 110
149
TABI,E F - 2
TABLU1,ATION OF C f I E M I C A L S REMOVED BY TR1':ATMI':N'T AND RENAINING IN EFFLUENTS AT
A TYPICAL P I I O T O F I N I S I I E R PROCESSING EK'I'AClIROME, KODACOLOR AND EKTACOLOR P R O D U C T S
Volume-gpm
Ammonium Ion-lh/day Borax Ion-lb/day Bromide Ion- lb/day Carbonate Ion-lb/day
m Ferrocyanide Ion-lb/day P
0
Nitrate Ion-lb/day Phosphate Ion-lb/day Sulfate Ion-lb/day Sulfite Ion-lb/day Silver Ion- lb/day
Thiosulfate Ion-lb/day Thiocyanate Ion-lb/day Zinc Ion-lb/day Acetate-lb/day Benzyl Alcohol-lb/day
Color Developer-lb/day Formaldehyde- lb/day Hydroqui O I I C - lb/day E l o n - l b / t ay Hydroxylamine sulfate-
1 b / d ay Sodium C i t r a t e - I b / d a y
BOD5 - lb/day
1 2 0
1 7 . 8 9 5 . 3 2 4 . 9 5 1 . 6 4 2 . 7
4 9 . 8 5 . 3
2 5 . 7 4 9 . 8 1.1
1 7 8 . 0 0 . 3 2 .8
1 4 2 . 0 3 5 . 6
2 0 . 3 9 2 . 5
3 . 5 3 . 9
6 . 0 3 3 . 8
247 .0
TOTAL % REblOVED (3) co N c E s 1' R A T li I ) I N D U S BY MAS'l'E AIC'I'fii< WASTE (1) TKEAlMIJN?' (2) WASFIISATER T K E AT :*I I: N 'I'
B C D
40 - -
60 9 5 1 5
none 9 5
1 5 1 5
none 1 0 0
9 5
80 1 5
1 5 40
none 80 10 1 0
none 1 0
5 5
- - - -
1 1 0
0 .2 0.1 0.3 0 . 9 0.09
0.6 0.06 0.3 - _ _ _ _ _ - - - _ - -
0 . 6 - - - - - - - - - - - - - _ 1.5 0.3
0.3 0.2s 0 -05 0 .os
0.1 0 - 4
2 - 0
1 0
6 . 9 . 4 . 7 20 .9 5 0 . 7
2 . 1
4 1 . 7 4 . 5
2 6 . 4
0 . 2
43.9
- - - - -
0 . ? 5 _ _ _ _ _ - 1 1 9 . 5
2 1 . 1
2 0 . 0 1 5 . 2 5
3 . 0 5 3 . 4 5
5 . 9 3 0 . 0
1 0 9 . 1
TABLE F-2
(con t inued)
1 Based on average processor operation o f 6 hrs/day
2. A: Electrolytic Silver Recovery with Fixer Recirculation
B: Ferricyanide Bleach Regeneration with Ozone or by Electrol;. c
C: Chemical Destruction with Strong Oxidant such as Ozone Chlorine, Peroxide or Permanganate.
D: Total of A , B G C
3 As percent of total amount present in industrial waste
SICLECTED W A T E R 1. Report No. K E S O U R C E S A B S T R A C T S I N P U T T R A N S A C T I O N FORM
3 Acce\sion Nc 2.
vv
H e n d r i c k s o n , Thomas N . D a i a n a u l t . Louis G .
9. Oraani za t ion
17a. D e s c r i p t o r s
* A n a l y t i c a l T e c h n i q u e s , *Chemical P r e c i p i t a t i o n , * C h l o r i n a t i o n , * O x i d a t i o n , *Ozone, * E l e c t r o l y s i s , c h l o r i n e , c o a g u l a t i o n , Chemical Waste , L a b o r a t o r y T e s t s , E l e c t r o C h e m i s t r y , F l o c c u l a t i o n , Heavy M e t a l s , T o x i c i t y , C o s t s , Water T r e a t m e n t , B iochemica l Oxygen Demand, Chemical
P7PX%t ;eEmand - * P h o t o f i n i s h i n g Wastes, " F e r r i c y a n i d e , Chemical Recovery , "Complex Cyanides , Waste Recycle .
10. P r o j e c t N o .
E P A , 1 2 1 2 0 E R F
17c. C O W R R Field di Group
18. Ava i lab i l i t y 19. Security Class. 21 . N o . of Send T o : Pages I (Repor t )
Berkey F i l m P r o c e s s i n g o f N . E . 2 6 0 Lunenburg S t r e e t
WATER RESOURCES SCIENTIFIC I N F O R M A T l O h CENTER 20. Security Class. 22. Price DEPARTMENT T H E
(Pagel I WASHINGTON D C 2n74n
1 1 . C o n t r a c t l G r a n t N o