title: Photochemical transformation of tetrabromobisphenol A under simulated sunlight irradiation: Kinetics, mechanism and influencing factors.
abstract: A systematic study on photolysis of tetrabromobisphenol A (2,2',6,6'-tetrabromo-4,4'-isopropylidendiphenol, TBBPA) in water was investigated under simulated sunlight irradiation. The results showed that the photolysis of TBBPA followed apparent pseudo-first-order kinetics. The photolysis rate constants (k) changed from 2.80 × 10(-2) to 0.70 × 10(-2)min(-1) with the concentrations of TBBPA varying from 0.1 to 10 mg L(-1). Increasing humic acid (HA) concentration from 0-100 mg L(-1) led to the decrease of k from 2.53 × 10(-2) to 0.39 × 10(-2)min(-1), which was due to the competitive adsorption for photons between HA and TBBPA molecules. The photolysis rate was faster at near-neutral conditions (pH=6 and 7) than that in either acidic or basic conditions. Electron spin resonance (ESR) and reactive oxygen species (ROS) scavenging experiments indicated that TBBPA underwent self-sensitized photooxidation via ROS (i.e., OH, (1)O2 and O2(-)), and the process was mainly controlled by O2(-). After irradiation of 180 min, about 35.0% reduction of TOC occurred accompanied with approximate 99.1% of TBBPA removed. The detection of products (i.e., Br(-), bisphenol A, 2,6-dibromophenol, 2-bromophenol and phenol) revealed that the main photolytic pathways of TBBPA were debromination and breakage of C-C bond.
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
authors.forename: Yueping
authors.initials: Y
authors.lastname: Bao
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China. Electronic address: junfengn@bnu.edu.cn.
authors.forename: Junfeng
authors.initials: J
authors.lastname: Niu
mesh_terms: D006812:Humic Substances / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010782:Photolysis; D011075:Polybrominated Biphenyls / Q000528:radiation effects*; D017382:Reactive Oxygen Species / Q000737:chemistry; D013472:Sunlight; D014874:Water Pollutants, Chemical / Q000528:radiation effects*
chemical_list: D006812:Humic Substances; D011075:Polybrominated Biphenyls; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; C020806:tetrabromobisphenol A
keywords: Debromination; Kinetics; Mechanisms; Photolysis; Tetrabromobisphenol A