Contribution of different reactive species in the oxidation of bisphenol A by permanganate combined with 1-hydroxybenzotriazole

• Reactive species included Mn(VII), MnO 2 , and HBT • radical in Mn(VII)/HBT system. • Relative contributions (R) ranked as R(HBT • ) > R(Mn(VII)) > R(MnO 2 ) at pH 4.0–6.0. • R(Mn(VII)) was higher than R(HBT • radical) at pH 7.0–9.0. • The relative contribution could be largely affected by the reaction conditions. 1-Hydroxybenzotriazole (HBT), as one of the synthetic redox-mediators, significantly accelerates the oxidation of bisphenol A (BPA) during treatment with permanganate (Mn(VII)). The reaction between Mn(VII) and HBT produces HBT • radical and MnO 2 intermediates which can accelerate BPA oxidation by reacting with the organic contaminants in parallel with Mn(VII). This study aimed at quantifying the relative contributions of the reactive species in oxidizing BPA at different pH conditions. At pH ≤ 6, the relative contributions (R) ranked as R(HBT • radical) > R(Mn(VII)) > R( in-situ formed MnO 2 ), but at higher pH conditions the order switched. At pH ≥ 7, R(Mn(VII)) > R(HBT • radical) and in-situ formed MnO 2 contributed negligibly. These findings fill a critical knowledge gap and provide mechanistic insights into organic contaminant treatment processes combining permanganate with redox-mediators like HBT.