Decomposition of hexachlorobenzene (HCB) was investigated over several metal oxides (i.e., MgO, CaO, BaO, La{sub}2O{sub}3, CeO{sub}2, MnO{sub}2, Fe{sub}2O{sub}3, and Co{sub}3O{sub}4) supported on Al{sub}2O{sub}3, which was achieved in closed system at a temperature of 300°C. Catalysts were prepared by incipient wetness impregnation with different metal oxides loading and impregnating solvents. The decomposition efficiency of different catalysts for this reaction depends on the nature of the metal oxide used, and Al{sub}2O{sub}3 supported La{sub}2O{sub}3 was found to be the most active one. Pentachlorobenzene (PeCB), and all tetrachlorobenzene (TeCB), trichlorobenzene (TrCB), and dichlorobenzene (DCB) isomers were detected after the decomposition reaction, indicating that the decomposition was mainly a dechlorination process. The detection of all lower chlorinated benzenes suggested the complexity of decomposition and the presence of more than one dechlorination pathway.
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