title: Mechanistic study of photo-oxidation of Bisphenol-A (BPA) with hydrogen peroxide (H2O2) and sodium persulfate (SPS).
abstract: The removal of Bisphenol-A (BPA) from contaminated water using advanced oxidation methods such as UV-C assisted oxidation by hydrogen peroxide (H2O2) and sodium persulfate (SPS) has been reported by the authors earlier (Sharma et al., 2015a). In the present study, the authors report the removal of BPA from aqueous solution by the above two methods and its degradation mechanism. UV-C light (254 nm wavelength, 40 W power) was applied to BPA contaminated water at natural pH (pHN) under room temperature conditions. Experiments were carried out with the initial BPA concentration in the range of 0.04 mM-0.31 mM and the oxidant/BPA molar ratio in the range of 294:1-38:1 for UV-C/H2O2 and 31.5-4.06:1 for UV-C/SPS systems. The removal of BPA enhanced with decreasing BPA concentration. The total organic carbon also decreased with the UV-C irradiation time under optimum conditions ([H2O2]0 = 11.76 mM; [SPS]0 = 1.26 mM; temperature (29 ± 3 °C). Competition of BPA for reaction with HO or [Formula: see text] radicals at its higher concentrations results in a decrease in the removal of BPA. The intermediates with smaller and higher molecular weights than that of BPA were found in the treated water. Based on GC-MS and FTIR spectra of the reaction mixture, the formation of hydroxylated by-products testified the HO mediated oxidation pathway in the BPA degradation, while the formation of quinones and phenoxy phenols pointed to the [Formula: see text] dominating pathway through the formation of hydroxycyclohexadienyl (HCHD) and BPA phenoxyl radicals. The main route of BPA degradation is the hydroxylation followed by dehydration, coupling and ring opening reactions.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Roorkee, Roorkee, 247667, India.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Sharma
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Roorkee, Roorkee, 247667, India; Department of Chemical Engineering, Indian School of Mines, Dhanbad, Jharkhand, India. Electronic address: immishra49@gmail.com.
authors.forename: I M
authors.initials: IM
authors.lastname: Mishra
authors.affiliation: Department of Chemical Engineering, Indian School of Mines, Dhanbad, Jharkhand, India.
authors.forename: Vineet
authors.initials: V
authors.lastname: Kumar
mesh_terms: D001559:Benzhydryl Compounds / Q000032:analysis / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry / Q000528:radiation effects; D008401:Gas Chromatography-Mass Spectrometry; D006861:Hydrogen Peroxide / Q000737:chemistry* / Q000528:radiation effects; D016877:Oxidants; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis / Q000737:chemistry*; D017670:Sodium Compounds / Q000737:chemistry* / Q000528:radiation effects; D013431:Sulfates / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D005609:Free Radicals; D006861:Hydrogen Peroxide; D016877:Oxidants; D010636:Phenols; D017670:Sodium Compounds; D013431:Sulfates; D014874:Water Pollutants, Chemical; C042329:phenoxy radical; C024625:sodium persulfate; C006780:bisphenol A; D000098826:Bisphenol A Compounds
keywords: Advanced oxidation process (AOP); BPA; Degradation pathway; GC-MS; Hydrogen peroxide; UV