title: The degradation of 1,2,4-trichlorobenzene using synthesized Co3O4 and the hypothesized mechanism.
abstract: Co(3)O(4) was synthesized with cabbage-like, plate-like and sphere-like morphologies. The effect of different morphologies on the degradation of 1,2,4-trichlorobenzene (1,2,4-TrCB) was evaluated, and the cabbage-like Co(3)O(4) exhibited the highest reactivity. The degradation of 1,2,4-TrCB on the cabbage-like Co(3)O(4) is hypothesized to act competitively via hydrodechlorination and oxygen-attacking pathways. By the hydrodechlorination pathway, 1,2,4-TrCB is successively dechlorinated into the three dichlorobenzenes (DCBs) and then monochlorobenzene (MCB). The yield of the DCBs was in the order of p-DCB>m-DCB>o-DCB, which can be explained by the calculated C-Cl bond dissociation energies in 1,2,4-TrCB and DCBs. Derivatization and electron spin resonance experiments identified that lattice oxygen and superoxide anions may take part in the oxidation pathway. The lattice oxygen initiated a partial oxidation of 1,2,4-TrCB, leading to the formation of chlorinated phenols. The superoxide anions caused ring-cracking oxidation of 1,2,4-TrCB, possibly producing some low-molecular-weight products, thus explaining a mass imbalance in the chlorine atoms and total organic carbon.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085, China.
authors.forename: Shijing
authors.initials: S
authors.lastname: Lin
authors.forename: Guijin
authors.initials: G
authors.lastname: Su
authors.forename: Minghui
authors.initials: M
authors.lastname: Zheng
authors.forename: Manke
authors.initials: M
authors.lastname: Jia
authors.forename: Chuansong
authors.initials: C
authors.lastname: Qi
authors.forename: Wei
authors.initials: W
authors.lastname: Li
mesh_terms: D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D002623:Chemistry Techniques, Analytical; D002713:Chlorine / Q000032:analysis / Q000737:chemistry; D002722:Chlorobenzenes / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D007220:Industrial Waste; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D017382:Reactive Oxygen Species; D013481:Superoxides / Q000737:chemistry; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000032:analysis; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D002722:Chlorobenzenes; D007220:Industrial Waste; D010087:Oxides; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; C009947:1,2,4-trichlorobenzene; D013481:Superoxides; D003035:Cobalt; D002713:Chlorine; D002244:Carbon; D010100:Oxygen; C060728:cobalt oxide