Mn2O3/Mn3O4-Cu1.5Mn1.5O4 spinel as an efficient Fenton-like catalyst activating persulfate for the degradation of bisphenol A: Superoxide radicals dominate the reaction

In this work, a Mn2O3/Mn3O4-Cu1.5Mn1.5O4 spinel was fabricated and utilised as a catalyst to activate peroxydisulfate (PDS) leading to degradation of bisphenol A (BPA). The results showed that the system exhibited an excellent turnover frequency (TOF) of 2.7 × 10-3 s-1 and high stability. The amount of ion leaching was small and the degree of mineralisation was up to 66.2%. Superoxide radicals (O2-) were determined to be the dominant active species in the system. ≡Mn(II) and oxygen vacancies (Vo) were found to be the main active sites at the catalyst surface. The activation of PDS by the spinel catalyst and the reduction of dissolved oxygen both contributed to the production of O2- species. The synergistic effect of ≡Cu(I)/≡Cu(II) and ≡Mn(II)/≡Mn(III) redox pairs enabled the reaction to occur continuously. These results suggest the promise of this novel spinel catalyst in the removal of refractory organic compounds due to its excellent performance and stability. The catalyst may thus have great utility for environmental remediation.