Affiliations: State Key Laboratory of Pollution Control and Resource
Reuse, School of the Environment, Nanjing University, Nanjing 210093,
China | Jiaying University, Meizhou 514015, China
Abstract: 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 (O_2^{·-}) 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.
Keywords: bisphenol A, Fe(III)-oxalate complexes, photooxidation, reactive oxygen species
