Photodegradation of bisphenol a induced by iron(III) in the presence of cyclodetrin in aqueous solution

The photolysis of Fe (OH) 2, in aqueous solution under a 250W metal halide lamp (lambda >= 365 nm) can produce active center dot OH radicals, which can oxidize endocrine disrupter bisphenol A (BPA). In the presence of beta-cyclodextrin (beta-CD), the photodegradation efficiency of BPA can be enhanced obviously. The effects of initial pH values, concentrations of beta-CD, BPA and Fe (111) were investigated. At pH 3.0 in aqueous solution, Fe (OH)(2+) was the dominant Fe (III) species, BPA molecules were included by P-CD, and brought closer to the Fe (OH)(2+). Therefore, center dot OH radicals generated from the photolysis of Fe (OH)(2+) can react more rapidly and easily with BPA, which led to the degradation of BPA rapidly. The inclusion complex was characterized with UV-vis absorption spectrum and fluorescence spectra, and its inclusion structure was calculated and optimized with quantum chemistry software Gaussian98. The result showed that BPA entered partly into the cavity of beta-CD, which formed supramolecular host-guest complexes, and resulted in the enhancement of photodegradation rate of BPA under UV-vis irradiation.