Catalytic oxidation of chlorinated volatile organic compounds over MOx-CeO2/HZSM-5 catalysts
MOx-CeO2/HZSM-5催化剂催化氧化含氯挥发性有机物研究

The catalytic performance of MOx-CeO2/HZSM-5 (M= Cr, Mn, Fe, Co, Ni and Cu) catalysts prepared by an impregnation method were evaluated in the oxidation of 1,2-dichloroetane (DCE). The introduction of secondary transition-metal-oxide component can greatly improve the catalytic activity of CeO2/HZSM-5 for DCE destruction. The catalytic activities of MOx-CeO2/HZSM-5 catalysts decrease as the order of 9%Ni-12%CeO2/HZSM-5 > 9%Co-12%CeO2/HZSM-5, 9%Mn-12%CeO2/HZSM-5 > 9%Cu-12%CeO2/HZSM-5, 9%Cr-12%CeO2/HZSM-5 > 9%Fe-12%CeO2/HZSM-5 > 12%CeO2/HZSM-5. Large amounts of polychlorohydrocarbon such as C2HCl3 and C2Cl4 were generated over Ni, Co, Mn and Cu impregnated catalysts. Moreover, small concentration of C2H2Cl4 was found when 9%Cu-12%CeO2/HZSM-5 was used as the catalyst. The generation of polychlorohydrocarbon can cause secondary pollution. Among all the catalysts, 9%Cr-12%CeO2/HZSM-5 not only displayed high activity for DCE destruction, but also produced the least polychlorohydrocarbons and showed high selectivity to CO2 and HCl. The improved capability of dehydrochlorination and the deep oxidation of DCE were attributed to strong interactions between CrOx and CeO2, which prompted the migration of active oxygen species on 9%Cr-12%CeO2/HZSM-5 surface.