The aqueous photodegradation of bisphenol A （BPA） in the presence of Fe（Ⅲ）-oxalate complexes （Fe（Ⅲ）-Ox）, which are common compositions of natural water, was investigated in this study. BPA underwent rapid in...The aqueous photodegradation of bisphenol A （BPA） in the presence of Fe（Ⅲ）-oxalate complexes （Fe（Ⅲ）-Ox）, which are common compositions of natural water, was investigated in this study. BPA underwent rapid indirect photolysis in Fe（Ⅲ）-Ox solution under simulated solar irradiation, proceeding pseudo-first-order kinetics. The photolysis rate increased with decreasing pH or initial BPA level and increasing Fe（Ⅲ）/oxalate concentration ratio. Hydroxyl radicals （·OH）, which were generated from the photochemical processes of Fe（Ⅲ）-Ox complexes and contributed to the photooxidation of BPA, were determined by molecular probe and electron spin resonance （ESR） methods with the steady-state concentration of 2.56 × 10^-14 mol/L. Superoxide anion radical （O2^·-） was considered as the precursor of. OH and qualitatively determined by adding nitro blue tetrazolium as well as ESR experiments. Based on the structural analysis of the intermediate photoproducts of BPA in Fe（Ⅲ）-Ox complexes solution, the possible degradation pathways of BPA were proposed, involving ·OH addition, alkyl scission and alky oxidation. The results indicate that the photochemical reactivity of Fe（Ⅲ） may affect the environmental fate of BPA in natural water significantly.展开更多
Two azo dyes,C.I.Reactive Red 195(RR195)and C.I.Acid Black 234(AB234)were degraded by photocatalysis of Fe(Ⅲ)-oxalate complexes/H2O2 in aqueous non-ionic surfactant,Triton X-100(TX-100)solution.Some factors affecting...Two azo dyes,C.I.Reactive Red 195(RR195)and C.I.Acid Black 234(AB234)were degraded by photocatalysis of Fe(Ⅲ)-oxalate complexes/H2O2 in aqueous non-ionic surfactant,Triton X-100(TX-100)solution.Some factors affecting the dye degradation such as TX-100 concentration,irradiation intensity,and sodium chloride were investigated.The interaction and competition between dye and TX-100 during the degradation were also examined using spectrophotometry and maximum bubble pressure method,respectively.The results indicated that TX-100 showed a significant reduction effect on degradation of two azo dyes,but which was largely confined to TX-100 concentration below the Critical Micellar Concentration(CMC).And the reduction was considerably decreased above the CMC,especially in the case of AB234.Moreover,the reducing effect of TX-100 on dye degradation almost did not vary with irradiation intensity.And the impact of sodium chloride on dye degradation was limited by the addition of TX-100.展开更多
文摘The aqueous photodegradation of bisphenol A （BPA） in the presence of Fe（Ⅲ）-oxalate complexes （Fe（Ⅲ）-Ox）, which are common compositions of natural water, was investigated in this study. BPA underwent rapid indirect photolysis in Fe（Ⅲ）-Ox solution under simulated solar irradiation, proceeding pseudo-first-order kinetics. The photolysis rate increased with decreasing pH or initial BPA level and increasing Fe（Ⅲ）/oxalate concentration ratio. Hydroxyl radicals （·OH）, which were generated from the photochemical processes of Fe（Ⅲ）-Ox complexes and contributed to the photooxidation of BPA, were determined by molecular probe and electron spin resonance （ESR） methods with the steady-state concentration of 2.56 × 10^-14 mol/L. Superoxide anion radical （O2^·-） was considered as the precursor of. OH and qualitatively determined by adding nitro blue tetrazolium as well as ESR experiments. Based on the structural analysis of the intermediate photoproducts of BPA in Fe（Ⅲ）-Ox complexes solution, the possible degradation pathways of BPA were proposed, involving ·OH addition, alkyl scission and alky oxidation. The results indicate that the photochemical reactivity of Fe（Ⅲ） may affect the environmental fate of BPA in natural water significantly.
基金National Natural Science Foundation of China(No.20773093)Tianjin Municipal Science Programme Foundation,China(No.043605911)
文摘Two azo dyes,C.I.Reactive Red 195(RR195)and C.I.Acid Black 234(AB234)were degraded by photocatalysis of Fe(Ⅲ)-oxalate complexes/H2O2 in aqueous non-ionic surfactant,Triton X-100(TX-100)solution.Some factors affecting the dye degradation such as TX-100 concentration,irradiation intensity,and sodium chloride were investigated.The interaction and competition between dye and TX-100 during the degradation were also examined using spectrophotometry and maximum bubble pressure method,respectively.The results indicated that TX-100 showed a significant reduction effect on degradation of two azo dyes,but which was largely confined to TX-100 concentration below the Critical Micellar Concentration(CMC).And the reduction was considerably decreased above the CMC,especially in the case of AB234.Moreover,the reducing effect of TX-100 on dye degradation almost did not vary with irradiation intensity.And the impact of sodium chloride on dye degradation was limited by the addition of TX-100.
