title: Oxidation of benzophenone-3 during water treatment with ferrate(VI).
abstract: Benzophenone-3 (BP-3), a sunscreen agent widely used in many cosmetic products, has been found to have a wide presence in aquatic environments, which could affect the water quality and human health. We investigated oxidation of BP-3 by aqueous ferrate(VI) (Fe(VI)) to determine reaction kinetics, identify the reaction products, and evaluate the removal efficiency of BP-3 during water treatment with Fe(VI). The obtained apparent second-order rate constant (kapp) for Fe(VI) oxidation of BP-3was 81.8 M(-1) s(-1) at pH 8.0 and 24 ± 1 °C with the half-life (t1/2) of 167.8 s for BP-3 at an Fe(VI) concentration of 10 mg L(-1). The kapp of the reaction decreased with increasing pH values. Species-specific rate constants (k) for the reaction of HFeO4(-) with each of BP-3's acid-base species were used to model these pH-dependent variations of kapp. The value of k determined for neutral BP-3 was 3.4(±0.5) × 10(2) M(-1) s(-1), while that measured for dissociated BP-3 was 8.5(±0.7) × 10(3) M(-1) s(-1). The reaction between HFeO4(-) and the dissociated BP-3 controls the overall reaction. 4-Methoxybenzophenone and 4-methoxybenzoyl cation were formed during Fe(VI) degradation of BP-3. The removal efficiency of BP-3 by Fe(VI) treatment was dependent on coexisting constituents present in source water. Humic acids, Mn(2+) and NaCl significantly decreased the removal efficiency of BP-3, while Br(-) and Cu(2+) enhanced the removal. Besides, NH4(+), NO3(-), Fe(3+) and Fe(2+) had no effects on BP-3 removal within the tested concentrations. The results showed that Fe(VI) treatment technology appears to be a promising tool for the removal of hydroxylated benzophenone derivatives in water.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Guang-Guo
authors.initials: GG
authors.lastname: Ying
mesh_terms: D001577:Benzophenones / Q000737:chemistry* / Q000302:isolation & purification*; D002412:Cations; D060587:Groundwater / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D012995:Solubility; D021241:Spectrometry, Mass, Electrospray Ionization; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification*; D018508:Water Purification
chemical_list: D001577:Benzophenones; D002412:Cations; D014874:Water Pollutants, Chemical; C017311:ferrate ion; C005290:oxybenzone; D007501:Iron