Photodegradation of bisphenol A in Fe(Ⅲ)-oxalate complexes solution

The aqueous photodegradation of bisphenol A (BPA) in the presence of F e(Ⅲ)-oxalate complexes (Fe(Ⅲ)-Ox), which are common compositions of natural wa ter, was investigated in this study. BPA underwent rapid indirect photolysis in Fe(Ⅲ)-Ox solution under simulated solar irradiation, proceeding pseudo-first-or der kinetics. The photolysis rate increased with decreasing pH or initial BPA le vel 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 pro be and electron spin resonance (ESR) methods with the steady-state concentration of 2.56×10-14 mol/L. Superoxide anion radical(O2·-) was consi- dered as the p recursor of ·OH and qualitatively determined by adding nitro blue tetrazolium a s well as ESR experiments. Based on the structural analysis of the intermediat e 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.