Removal mechanism and quantitative control of trichloroethylene in a post-plasma-catalytic system over Mn-Ce/HZSM-5 catalysts

It is urgent to control trichloroethylene (TCE) due to its harmful effect on the environment and humans. Here, a post-plasma-catalytic (PPC) system combining Mn-Ce/HZSM-5 catalysts and a corona discharge reactor was developed for TCE degradation. Among the tested catalysts, MnCe1/HZSM-5 (Ce/Mn molar ratio = 1) showed the best catalytic performance due to its better reducibility and higher content of adsorbed oxygen. The PPC configuration markedly lowered the activation temperature of the catalyst. Then, the optimization of the TCE degradation process in the PPC system was performed using response surface methodology. The results showed that the discharge power was the dominant factor affecting the TCE degradation process, followed by the gas flow rate and relative humidity (RH). The optimum TCE removal efficiency of 99.9%, CO2 yield of 52.84% and CO yield of 22.74% were obtained under the following operating conditions: discharge power 1.13 W, gas flow rate 0.5 L min-1 and RH 18.77%. The stability of the PPC system over the MnCe1/HZSM-5 catalyst was successfully evaluated by a long-time test. Finally, the TCE degradation pathway in the PPC system was also proposed. This study strengthens the understanding of the TCE decomposition mechanism and paves a way for quantitative control of TCE in the PPC system.