Efficient degradation of Bisphenol A by Fe3+/Fe2+ cycle activating persulfate with the assistance of biochar-supported MoO2

Advanced oxidation processes (AOPs) based on persulfate (PDS) activation by iron materials have attracted significant attention due to their high organic pollution removal efficiency and relatively low remediation costs. However, one of the iron-based materials’ shortcomings is the weak activation ability of Fe 3+ on PDS and the low sustainability of Fe 2+ in the oxidation environment. In this study, biochar-supported molybdenum dioxide (MoO 2 @BC) was employed as a co-catalyst to enhance the Fe 3+ based PDS activation for Bisphenol A (BPA) degradation. Results showed that >96 % of BPA was removed during 60 min, and the BPA degradation efficiencies only slightly decreased after four reuses of MoO 2 @BC. Electron paramagnetic resonance (EPR) analysis and quenching experiments indicated that reactive oxidation species (ROSs) contributing to the degradation of BPA were SO 4 − , OH and 1 O 2 . Besides, it was found that biochar supporting favours the adsorption of Fe 3+ on the MoO 2 surface and promotes the electron transfer from Mo(IV) to Fe 3+ based on the combination of X-ray photoelectron spectroscopy (XPS) analysis, electrochemical tests and density functional theory calculation (DFT). This work provides a new insight for enhancing the performance of organic contaminants degradation through AOPs based on persulfate activation by iron material.