Dechlorination of chlorobenzene in subcritical water with Fe/ZrO2, Ni/ZrO2 and Cu/ZrO2.
To obtain information about dechlorination of organochlorine compounds in subcritical water catalyzed by metals assisted with ZrO(2), dechlorination of chlorobenzene has been investigated in the presence of Fe/ZrO(2), Ni/ZrO(2) and Cu/ZrO(2) catalysts. The dechlorination efficiency was increased with increasing residence time, temperature and pressure. The order of effectiveness of the catalysts was Cu/ZrO(2) < Ni/ZrO(2) < Fe/ZrO(2). The dechlorination of chlorobenze obeyed pseudo-first-order kinetics models. The rate constants in subcritical water were much greater than that in ambient-temperature water; the activation energies were obtained. ZrO(2) in the catalyst had the power to absorb chlorobenzene onto the catalyst surface and promoted the dechlorination ability of the metal. The primary mechanism for dechlorinaton of chlorobenzene involved the reduction of chlorobenzene by reaction with nascent hydrogen. The nascent hydrogen reacted with the chlorobenzene, which adsorbed on the catalyst in non-planar and co-planar form, and formed benzene and chloride ions.
Wei
Guang-Tao
GT
College of Environmental Science and Engineering, South China University of Technology, Guangzhou, Guangdong 510006, P. R. China. cechwei@scut.edu.cn
Wei
Chao-Hai
CH
He
Feng-Mei
FM
Wu
Chao-Fei
CF
D002384:Catalysis; D002722:Chlorobenzenes / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
D002722:Chlorobenzenes; D014874:Water Pollutants, Chemical; D003300:Copper; D009532:Nickel; D015040:Zirconium; D007501:Iron; C031294:chlorobenzene; C028541:zirconium oxide