title: Photolytic reaction mechanism and impacts of coexisting substances on photodegradation of bisphenol A by Bi2WO6 in water.
abstract: Bi(2)WO(6) displayed great photolytic degradation efficiency to bisphenol A (BPA) under simulated solar light irradiation but its reaction mechanism and the impacts of coexisting substances on the degradation remain unclear. In present study, the reaction mechanism was investigated using DMPO spin-trapping ESR spectra and experiments with scavengers of hydroxyl radicals (*OH) and holes. The results supported that hole oxidation mainly governed the photodegradation process. As a common humic substance in natural water, humic acid accelerated the degradation of BPA when its concentration was 1mg/L, while the photodegradation was impeded with the increase of humic acid concentration in the range of 5-20mg/L. Almost all anions, including NO(3)(-), HCO(3)(-), Cl(-), SO(4)(2-) inhibited the degradation of BPA by Bi(2)WO(6) and their inhibition effects followed the order of SO(4)(2-)>Cl(-)>HCO(3)(-)>NO(3)(-). Cations of Na(+), K(+), Ca(2+) and Mg(2+) displayed slight suppressing effect on BPA degradation mainly due to the impact of Cl(-) coexisting in the solution. However, Cu(2+) hindered the BPA photodegradation heavily. Fe(3+) and H(2)O(2) affected the photodegradation in a complicated way: they suppressed or promoted the photodegradation depending on their concentrations. This could be the result of competition between photolyitc hole generated by Bi(2)WO(6) and OH produced by Fe(3+) or H(2)O(2.).
authors.affiliation: College of Environmental Science and Engineering, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071, PR China.
authors.forename: Chunying
authors.initials: C
authors.lastname: Wang
authors.forename: Lingyan
authors.initials: L
authors.lastname: Zhu
authors.forename: Mingcui
authors.initials: M
authors.lastname: Wei
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Shan
mesh_terms: D001559:Benzhydryl Compounds; D001729:Bismuth / Q000737:chemistry*; D002412:Cations; D003300:Copper / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D006812:Humic Substances / Q000032:analysis; D006861:Hydrogen Peroxide / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D010636:Phenols / Q000737:chemistry*; D010782:Photolysis; D013113:Spin Labels; D017973:Tungsten Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D001729:Bismuth; D002412:Cations; D003300:Copper; D006812:Humic Substances; D006861:Hydrogen Peroxide; D007501:Iron; D010636:Phenols; D013113:Spin Labels; D017973:Tungsten Compounds; D014867:Water; D014874:Water Pollutants, Chemical; C006780:bisphenol A; D000098826:Bisphenol A Compounds