Evaluation of a newly developed diffusion denuder for atmospheric aerosol separation from co-pollutant gases

This paper presents the design, development and performance evaluation of a non-selective membrane based single annular tube diffusion denuder employed to separate co-pollutant gases from the aerosol of interest. The experiments were carried out on a single annular tube diffusion denuder and the gas removal efficiencies were experimentally determined using a laboratory scale setup as well as under ambient conditions. Using a simple combustion source, the removal efficiency of carbon monoxide was calculated for different main flow (MF) and flush flow (FF) combinations and was found to be in the range of 94-100%. The overall soot particle transmission efficiency was found to be in the range of 70-99% for particle size between 0.3 μm and 2 μm. Overall, transmission efficiencies for submicron particles were also evaluated using an ultrafine condensation particle counter. After the controlled laboratory testing of the prototype denuder, experiments were conducted using ambient air as the test aerosol. This prototype denuder provided a much higher efficiency of gaseous removal in a single stage as compared to earlier reported values. Its simple and easy operation makes it a promising device to use as compared with other commonly employed chemical adsorption based alternate tools.