Ru(III)-catalyzed permanganate oxidation of bisphenol A

This study employed Ru(III) as catalyst in permanganate oxidation of bisphenol A (BPA) for the first time. Ru(III) could significantly improve the reaction rate of BPA oxidation by 1.2–6.3 times with its concentration varying from 2.5 to 15 μM. The oxidation of BPA by Ru(III)-catalyzed permanganate followed pseudo-first order with respect to BPA or permanganate and second order with respect to Ru(III). BPA removal by Ru-catalyzed permanganate oxidation was heavily dependent on pH, which may be associated with the variation of permanganate oxidation potential with pH. The effect of temperature on BPA removal by Ru(III)-catalyzed permanganate was investigated, and the activation parameters were calculated. BPA removal in the catalytic oxidation was enhanced in the presence of 1–10 mg C L−1 humic acid. Although the catalytic ability of Ru(III) in tap water was inferior to that in DI water, the presence of 5 μM Ru(III) did increase the second-order rate constant of BPA oxidation from 36.7 to 40.8 M−1 s−1 in tap water. The degradation by-products of BPA in catalytic permanganate oxidation were identified. Finally, the catalytic mechanism was tentatively proposed.