Effect of atmospheric surface plasma on the adsorption of ethanol at activated carbon filter element

Abstract

Atmospheric non-thermal plasma has been recognized as a successful tool for the treatment of exhaust and waste air for abatement of pollutants, air cleaning, and odor removal. To improve the efficiency of plasma cleaning processes a combination of plasma with adsorption filters and or catalysts is used. The fundamental interaction mechanisms of the surface, plasma, and gas remain the subject of further investigations of the details. A quantitative FTIR-spectroscopic study of the effect of surface barrier discharge on the adsorption and desorption of ethanol at activated carbon is presented. First of all the adsorption and desorption were characterized for different input concentrations and different carrier gas flows without operating the plasma. After that the interaction of the plasma and the gas mixture was analyzed. Finally the activated carbon filter was reinstalled behind the plasma stage and the loading and unloading of the activated carbon filter element were investigated while burning the plasma. It is shown that the plasma stage initiates an additional decomposition of ethanol at the surface of the activated carbon because of the interaction of long-lived O3 with physical adsorbed C2H5OH. The total amount of filtered C2H5OH does not change but the portion of decomposed C2H5OH that is not rinsed out increases. The plasma caused effect at the surface reaches 68% of the effect of plasma in the gas phase.