Structural Transformation of MnO2 during the Oxidation of Bisphenol A

Bisphenol A (BPA) is an endocrine-disrupting compound widely used in the plastic industry:and found in natural waters at concentrations considered harmful for aquatic life. BPA is susceptible to oxidation by Mn(III/IV) oxides, which ate commonly found in near-surface environments. Here, we quantify BPA oxidation rates and the formation of its predominant product, 4-hydroxycumyl alcohol (HCA), in tandem with transformation of a, synthetic, Mn(III)-rich delta-MnO2. To investigate the effect of Mn oxide structural changes on BPA oxidation rate, 12 sequential additions of 80 mu M BPA are performed at pH 7. During the additions, BPA oxidation rate decreases by 3 orders of magnitude, and HCA yield decreases from 40% to 3%. This is attributed to the accumulation of interlayer Mn(II/III) produced during the reaction, as observed Using X-ray absorption spectroscopy, as well as additional spectroscopic and wet chemical techniques. HCA is oxidized at a rate that is 12.6 times slower than BPA and accumulates in solution. These results demonstrate that BPA degradation by environmentally relevant Mn(III/IV) oxides is inhibited by the buildup:,of solid-phase Mn(II/III);;specifically in interlayer sites. Nevertheless, Mn oxides may BPA migration in near-surface environments and have potential for use in drinking and, Wastewater treatment.