title: Kinetics and products of PCB28 degradation through a goethite-catalyzed Fenton-like reaction.
abstract: Efficiencies of 2,4,4'-trichlorobiphenyl (PCB28) degradation in a goethite-catalyzed Fenton-like system under various conditions were investigated. Up to 99% of PCB28 was degraded in the Fenton-like system after 48 h. The hydroxyl radical was responsible for the degradation of PCB28 at pH 3-7. Degradation of PCB28 and H2O2 followed pseudo-first-order kinetics. The rate of PCB28 degradation decreased when the pH increased from 3 to 7, but increased with increasing concentration of goethite and H2O2. The rate of H2O2 decomposition increased at higher pH and goethite concentration, and decreased at lower H2O2 concentration. The half-lives of 4-chlorobiphenyl, 4,4'-dichlorobiphenyl, 2,4,4'-trichlorobiphenyl, and 2,2',4,4'-tetrachlorobiphenyl were 1.8, 3.5, 4.1, and 11h, respectively; therefore, the number of chlorine atoms in the biphenyl molecule determined the chemical reactivity of PCBs. By gas chromatography-mass spectrometry, one monochlorobiphenyl, three dichlorobiphenyl, and two hydroxytrichlorobiphenyl derivatives were identified as major products of PCB28 degradation. The decrease in pH of the reaction mixture after 48h reaction revealed that acidic products might be formed during degradation.
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhi-Rong
authors.initials: ZR
authors.lastname: Lin
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Ma
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: zhaoling@issas.ac.cn.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yuan-Hua
authors.initials: YH
authors.lastname: Dong
mesh_terms: D001713:Biphenyl Compounds / Q000737:chemistry; D002713:Chlorine; D004785:Environmental Pollutants / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D017665:Hydroxyl Radical; D007501:Iron / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry*; D007700:Kinetics; D008903:Minerals / Q000737:chemistry*; D011078:Polychlorinated Biphenyls / Q000737:chemistry*
chemical_list: D001713:Biphenyl Compounds; D004785:Environmental Pollutants; C045076:Fenton's reagent; D058085:Iron Compounds; D008903:Minerals; C094886:goethite; D017665:Hydroxyl Radical; C035976:2,4,2',4'-tetrachlorobiphenyl; D002713:Chlorine; C081766:2,4,4'-trichlorobiphenyl; D006861:Hydrogen Peroxide; D011078:Polychlorinated Biphenyls; C029861:4,4'-dichlorobiphenyl; D007501:Iron; C006983:4-chlorobiphenyl
keywords: Fenton-like reaction; Goethite; Hydrogen peroxide; Polychlorinated biphenyls