Xu Ly Nuoc Thai Bang Pp Hoa Hoc

7/23/2019 Xu Ly Nuoc Thai Bang Pp Hoa Hoc

1/19

Cha ter 11

Xl nc thing p ng p p a c

1


2/19

Qu trnh ha hc

Trung ha Ph nng to k t t a:

Kh kim loi

Phospho Cyanua

Oxi ha

Oxi ha cht hu c

2


3/19

3


4/19

Kt ta Removal of Fluoride from Semiconductor Wastewater

CaF b CaCl

Heavy metals are typically precipitated from wastewater as:

H droxides

Sulfides (dng NaS2 hoc H2S)

Kt ta cng qu trnh keo t

4


5/19

5


6/19

Kt ta

Tc nhn to phc (cyanide salts) nnc loi b trc khi ktta kim lo iSulfide precipitation is always conducted under alkaline conditions

to promote sulfide ion formation.

ree car ona e ons are presen on y e p s g . caus c s

often added to raise the pH.

Sulfide reci itates tend to form colloidal articles re uirin the

addition of coagulants to settle.

Sulfide sludges are easier to dewater than hydroxide sludges.

than the corresponding hydroxide precipitates.Sulfide slud es are more rone to oxidation resultin in

6resolubilization of the metals as sulfates. Evolution of H2S is a potential hazard


7/19

Kt ta ion Chromium tncthi cng nghip

Ngun gc pht thi Cr+6: ngnh thp, dt nhum, sn ..2 Giaio n:Kh Cr+6 thnh Cr+3 bng cht kh FeSO4, Na2S2O5 (sodiumbisulfite) or SO2(sulfur dioxide). PhnngpH thp

Kt ta (Cr+3) bng vi

The effluent concentration is 0.2 ppm at pH 7.5

7


8/19

Phc kim loi

Nhiu kim loi chuyn tip (e.g., Cd, Co, Cu, Fe, Hg, Ni, Zn) dt o hc vi chelates nh h droxides sulfides chloridescyanides, EDTA (ethylenediaminetetraacetic acid).

Cc chelates c th b loi bng pp oxidation Tc nhn oxidants ng ng c or ne, ypoc or e, an ozone.

V d: Cyanide c loi b bng 2 giaion:Gd 1: H > 10

Gd 1: pH 8.5-9

8


9/19

Cyanide Removal

9


10/19

10


11/19

Phosphorous removal

Kt ta phosphate bng cht keo t aluminium, iron, calcium.

11


12/19

Phosphorous removal

12


13/19

COD reduction by OxidationSupercritical water oxidation (SWO)

Electrochemical oxidation

is the oxidation of organic and/or inorganic compounds in aqueous phase by oxygenor air, and higher pressure and temperature conditions

ChlorideOxygen

H2O2-basedPhotochemical

OxidationPhotocatalysis


14/19

Oxidation power

14


15/19

H O -based rocesses

H2O2/UV

H2O2 /O3 process

Fenton and photo-Fenton process.

The Fenton's reaction is used to treat a large variety of water pollution such asp eno s, orma e y e, , pes c es, ru er c em ca s an so on..

15


16/19

Oxidation

16


17/19

Generally Fentons oxidation process was composedof four stages: pH adjustment, oxidation reaction,

neutralization and coagulation, and precipitation.

17Typical ranges are 1 part Fe per 5-25 parts H2O2


18/19

H2O2 -based rocesses

Hn ch: H Fenton tc dngi vi mt shp cht hu

c nh: small chlorinated alkanes tetrachloroethanetrichloroethane), n-paraffins and short-chain carboxylic acids(maleic, oxalic, acetic, malonic).

Trong m t s tr ng hp, thc hi n oxy h a ho n to n ti utn nhiu ha cht v thi gian => Fenton kt hp pp sinh hc

18


19/19

Typical ranges are 1 part Fe per 5-25 parts H2O2

19

Documents

Xu Ly Nuoc Thai Bang Pp Hoa Hoc