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Process:1. Cellulose denuder impregnated with 6% phosphoric acid
2. 8-hour ammonia gas collection efficiency test with a feed concentration of 10 ppm and flow rate 2 L/min
3. Determine the downstream concentration by applying OSHA’s Validation Guidelines for Air Sampling Methods Utilizing Chromatographic Analysis
Reagents: 85% phosphoric acid
Methanol
98% sulfuric acid
Standard solution of ammonium ion
EXPERIMENTAL CONDITION
RESULTSDENUDER MATERIAL
Whatman grade 541 Whatman grade 40
EXPERIMENTAL SETUP
Denuder preparation caution
A New Cellulose Denuder for Measuring Ammonia Gas: the Validation Test
INTRODUCTION
Cheng-Tung Liu1, Chih-Hsiang Chien1, Alex Theodore1, Chang-Yu Wu1*, Yu-Mei Hsu2, Brian Birky3
OBJECTIVES
RESULTS
CONCLUSIONS
REFERENCES
The disadvantage of the traditional samplers, glass Honeycomb denuder or glass annular denuder, are expensive and fragile material
Confirm the mass conservation in this sampling procedure
Develop an inexpensive denuder which can collect 95% 10 ppm ammonia for 8 hours
Denuder performance
Filter paper could be deteriorated by high temperature. Air purge should be the better way for coating drying
20 folds well-spread denuder experiment showed that cellulose denuder can absorb 10ppm NH3 for 8 hours
20 folds and 40 folds condense-pack denuder experiment showed the same decline rate for 8-hour collection performance, which indicates the assemble of denuders is the important factor for absorption
The blank denuder test showed the experiment data is meaningful. The minimum meaningful weight is 801 ug. The minimum sampling time is 54 minutes.
Based on the mass balance of 20 folds well-spread experiment, the output/input is 88%. The reason of the 12% losses could be instrumental or operational error
1. X. Chen, D. Day, B. Schichtel, W. Malm, A.K. Matzoll, J. Mojica, C.E. McDade, E.D. Hardison, D.L. Hardison, S. Walters, M.V. Water, J.L. Collett jr. Seasonal ambient ammonia and ammonium concentrations in a pilot IMPROVE NHx monitoring network in the western United States. Atmospheric Environment 91 (2014) 118-126
Gases ammonia reacts rapidly with atmospherically-formed sulfuric and nitric acids to contribute to ambient levels of secondary particulate matter and, thus, result to visibility reduction
www.gelifesciences.comGas Flow
Diffusion
Cellulose membrane a) Filter paper under 65 oC for 24 hours
denuder mass balance
1Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment, University of Florida, Gainesville, FL, USA.2Wood Buffalo Environmental Association, Alberta, Canada 3Florida Industrial and Phosphate Research Institute, FL, USA
BENEFITS Ergonomically designed sampler allows accurate
measurement of ammonia gas
Design for ambient ammonia gas measurement
Effective, inexpensive, lightweight, and easy-to-assemble gas collector
ACKNOWLEDGEMENTThe researchers would like to thank the Florida Industrial and Phosphate Research Institute for funding this project. We would also like to thank Dr. Treavor Boyer for sharing the laboratory instruments
Cellulose denuder capacities for 10 ppm NH4+
The quantitative filter paper featuring high wet strength and chemical resistance• Ash content: <0.006%
• Particle retention: 22 um
• Air flow rate: 3.8 s/100ml/in2
The ashless filter paper with low speed and high retention• Ash content: <0.007%
• Particle retention: 8 um
• Air flow rate: 19.3 s/100ml/in2
Accordion Shape Denuder
Apparatus: Ion chromatography
Mass flow controller
Relative humidity meter
Rotameter
Experiment: 20 folds denuder under low relative humidity
40 folds denuder under low relative humidity
Feed ammonia gas calibration test
Source: URG corporation
b) Filter paper dried by air purge
0 1 2 3 4 5 6 7 8 970%
75%
80%
85%
90%
95%
100%
105%
Time (hr)
Co
llec
tio
n e
ffic
ien
cy
(%
)
Calibration• Method: Measured one hour feed ammonia
gas without denuder
• Results: Massoutput / Massinputx 100%= 89%
Blank• Signal/Noise=denuders/blank= 17.9
• Minimum meaningful weight of NH4+ from
denuders is 801 ug (for S/N>=3, NH4+ will be
>16.02 ppm)
• For S/N> 3, The minimum sampling time for 10 ppm ammonia gas with flow rate of 2 L/min is 54 mins
Reaction equation:
Directly measured the upstream and downstream concentration by ICP = Ndown / Nup x 100%Nup : upstream ammonium concentration.Ndown : downstream ammonium concentration
10 ppm NH3
2 L/min
20 folds
20 folds
40 folds
input
20
folds
well
-spr
ead
outp
ut 2
0 fo
lds w
ell-s
prea
d
input
20
folds
cond
ense
outp
ut 2
0 fo
lds co
nden
se
input
40
folds
cond
ense
outp
ut 4
0 fo
lds co
nden
se0
1000
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3000
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6000
7000
8000
denuderbubbler
Am
mo
niu
m (
ug
)
calculated