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

2000

3000

4000

5000

6000

7000

8000

denuderbubbler

Am

mo

niu

m (

ug

)

calculated