Synergistic activation of peroxymonosulfate by CuO@Fe2O3 for enhanced degradation of ofloxacin: Role of surface hydroxyl groups and environmental applicability

Abstract

This study develops a Cu/Fe bimetallic material for peroxymonosulfate (PMS) activation to degrade organic pollutants. Under identical conditions, the degradation kinetic constant of ofloxacin (OFX) by the bimetallic material CuO@Fe₂O₃ was 2.15-fold and 28.19-fold higher than those achieved with single-metal CuO and Fe₂O₃ catalysts, respectively. The synergistic effect of copper and iron species promoted the occurrence of catalytic reaction and improved the degradation efficiency. Through radical quenching experiments, deuterium oxide (D₂O) experiments, pre-mixing experiments, and calculations of radical contribution rates, it was confirmed that the reaction involves the synergistic action of both free radical and non-free radical pathways. Under alkaline conditions, surface hydroxyl groups are generated, which accelerate the reaction process, achieving a nearly 100% removal rate within 5 minutes. Potential degradation pathways of OFX were proposed through LC-MS identification of intermediates coupled with theoretical calculations. The low toxicity of degradation byproducts and the material's robust anti-interference capability, reusability, and structural stability collectively demonstrate its practical potential for water remediation applications.