Efficient degradation of multiple Cl-VOCs by catalytic ozonation over MnOx catalysts with different supports

Abstract

This paper investigated catalytic ozonation of different Cl-VOCs (chlorobenzene (CB), dichloroethane (DCE), dichloromethane (DCM) and trichloroethylene (TCE)) over series of supported MnOx catalysts.These Cl-VOCs with different molecule structures exhibited obviously difference in catalytic performances and byproducts formation. Interestingly, the correlation between catalytic behaviors and surface properties of catalysts was inconsistent for different Cl-VOCs. In comparison, Mn/HZSM-5(27) presented a better conversion and mineralization rate (MAR) for most of Cl-VOCs due to its abundant surface acidity and excellent pore structures. Catalytic co-ozonation of mixed Cl-VOCs over Mn/HZSM-5(27) showed co-existence of inhibitive and promotive effects. For instance, CB conversion occupied priority compared with DCE and TCE, and MAR was enhanced in the mixture. Thereafter, the temperature programmed desorption results of mixed Cl-VOCs proved competitive adsorption between molecules. Both competitive adsorption and difficulty of Cl-VOCs degradation were the determining factors in catalytic co-ozonation of Cl-VOCs. Besides, catalytic co-ozonation of Cl-VOCs with presence of H2O exhibited negligible impact. These observations provide valuable reference for industrial application with co-presence of multiple Cl-VOCs and water vapor.