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

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^[rad] radical and MnO₂ 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^[rad] radical) > R(Mn(VII)) > R(in-situ formed MnO₂), but at higher pH conditions the order switched. At pH ≥ 7, R(Mn(VII)) > R(HBT^[rad] radical) and in-situ formed MnO₂ 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.