Oxygen vacancies engineering in Mn3O4 for regulating peroxymonosulfate activation and efficient bisphenol A degradation

In this work, oxygen vacancies (VO)-rich Mn3O4 was synthesized via changing reactive solvent. The effects of VO amount on PMS activation mechanism and bisphenol A (BPA) degradation were explored. Introduction of moderate amount of VO in Mn3O4 facilitated charge transfer and the exposure of surface Mn3+ species, which could oxidize BPA. Meanwhile, VO content could affect the PMS adsorption and activation modes. PMS adsorbed on bridged Mn-Mn sites in Mn3O4-x with more VO was likely to extract electrons from BPA to oxidize it directly. SO4•–, •OH, and 1O2 made negligible contributions to BPA degradation due to the presence of these two oxidation processes, but they were effective in the VO-free Mn3O4 system. Mn3O4-x/PMS system had good anti-interference ability in the degradation of BPA in complicated matrixes. The normalization kinetic constant was 103.2 min−1 M−1, which was 8.3 times higher than that of VO-free Mn3O4. The good catalytic activity (BPA = 20 ppm, with a removal ratio of above 90.0% in 180 min) in the continuous-flow experiment further revealed the potential of Mn3O4-x/PMS in practical wastewater applications. This study provides a new method to regulate the amount of VO in Mn3O4 and presents deep insights into the influence of VO on PMS activation. © 2024 Elsevier B.V.