title: Sequential reduction-oxidation for photocatalytic degradation of tetrabromobisphenol A: kinetics and intermediates.
abstract: C-Br bond cleavage is considered as a key step to reduce their toxicities and increase degradation rates for most brominated organic pollutants. Here a sequential reduction/oxidation strategy (i.e. debromination followed by photocatalytic oxidation) for photocatalytic degradation of tetrabromobisphenol A (TBBPA), one of the most frequently used brominated flame retardants, was proposed on the basis of kinetic analysis and intermediates identification. The results demonstrated that the rates of debromination and even photodegradation of TBBPA strongly depended on the atmospheres, initial TBBPA concentrations, pH of the reaction solution, hydrogen donors, and electron acceptors. These kinetic data and byproducts identification obtained by GC-MS measurement indicated that reductive debromination reaction by photo-induced electrons dominated under N(2)-saturated condition, while oxidation reaction by photoexcited holes or hydroxyl radicals played a leading role when air was saturated. It also suggested that the reaction might be further optimized for pretreatment of TBBPA-contaminated wastewater by a two-stage reductive debromination/subsequent oxidative decomposition process in the UV-TiO(2) system by changing the reaction atmospheres.
authors.affiliation: State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
authors.forename: Yaoguang
authors.initials: Y
authors.lastname: Guo
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Lou
authors.forename: Dongxue
authors.initials: D
authors.lastname: Xiao
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Wang
authors.forename: Jianshe
authors.initials: J
authors.lastname: Liu
mesh_terms: D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D004785:Environmental Pollutants / Q000737:chemistry / Q000302:isolation & purification* / Q000528:radiation effects; D052918:Environmental Restoration and Remediation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D015394:Molecular Structure; D010083:Oxidants, Photochemical / Q000737:chemistry* / Q000528:radiation effects; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D011075:Polybrominated Biphenyls / Q000737:chemistry / Q000302:isolation & purification* / Q000528:radiation effects; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D004785:Environmental Pollutants; D010083:Oxidants, Photochemical; D011075:Polybrominated Biphenyls; C009495:titanium dioxide; D014025:Titanium; C020806:tetrabromobisphenol A