Application of wet effluent diffusion denuder for measurement of uptake coefficient of gaseous pollutants

The comparison of theoretical approaches describing the collection of analyte in the cylindrical wet effluent diffusion denuder (CWEDD) with experimental data is presented. Various absorption liquids were tested for the collection of formaldehyde (distilled-deionized water, H2SO4 solution), acetaldehyde (distilled-deionized water) and nitrous acid (distilled-deionized water, sodium carbonate and sodium bicarbonate solutions of various concentrations and sodium phosphate pH 6-8) in CWEDD. pH of absorption liquids significantly influences the collection of formaldehyde as well as nitrous acid. The collection efficiency of formaldehyde for 0.05 M H2SO4 as absorption liquid was generally higher than for distilled-deionized water. Absorption liquid pH markedly affected the collection efficiency of HONO too (with increasing pH the collection efficiency increase). Data derived by Gormley-Kennedy equation for all investigated compounds were overestimated especially for higher flow rates of air, data calculated with respect to Henry constant are not in good agreement with experimental data and are considerably depended on a determination of the Henry constant value. The CWEDD can be alternative tool for the determination of uptake coefficient. Obtained uptake coefficients were in good agreement with data found in other literature.