The remarkable oxidation of trichloroethylene in a post-plasma-catalytic system over Ag-Mn-Ce/HZSM-5 catalysts

Abstract

The degradation of trichloroethylene (TCE) is of paramount importance due to its harmful effect on human health and the environment. In this study, a remarkable oxidation of the toxic TCE was achieved by using a hybrid system integrating a corona discharge reactor and a series of Ag-Mn-Ce/HZSM-5 catalysts. The combination of plasma and catalysis significantly promoted TCE oxidation compared with the plasma alone system. A maximum TCE removal efficiency (100 %) and an energy yield of 204 g·kWh−1 were obtained in the plasma-catalytic system by using the Ag4MnCeOx/HZSM-5 (4 wt% Ag loading) catalyst in dry air with a weight hourly space velocity of 200000 mL·g−1·h−1. In contrast, the plasma alone system showed only a removal efficiency of 34.8 % and an energy yield of 83 g·kWh−1 under the same conditions. By adding Ag, the surface adsorbed oxygen was activated and the reducibility of catalyst was promoted, which enhanced oxygen mobility and improved the oxidation of TCE. Furthermore, relative humidity (RH) had an important effect on TCE oxidation. The highest CO2 selectivity (71.86 %) and CO selectivity (22.21 %) were obtained at an RH of 20 %. The decomposition pathway of TCE in the post-plasma-catalytic system was proposed. This study is expected to provide a feasible method for the control of chlorine-containing waste gas.