Preparation of Oil Sludge-Based Activated Carbon Loaded with CuO/Fe2O3 and Its Mechanism in Activating Peroxymonosulfate for p-Nitrophenol Degradation

In this study, oil sludge was utilized as a carbon source to prepare a carbon-based catalyst. By leveraging the oil sludge’s inherent iron content and subsequently introducing exogenous copper, a CuO/Fe 2 O 3 /carbon composite material (OSC-0.75Cu) was synthesized for the activation of peroxymonosulfate (PMS) to degrade p-nitrophenol. The OSC-0.75Cu/PMS system achieved a degradation efficiency of 92.19%, which was 2.91 times that of the OSC/PMS system (31.71%), and its reaction rate constant (k obs ) was 8.9 times greater. Furthermore, in simulated water matrices (containing anions and fulvic acid) and three real water matrices (rainwater, moat water, and Yangtze River water), the OSC-0.75Cu/PMS systemachieved PNP degradation efficiencies ranging from 71.63% to 76.36%. The degradation of p-nitrophenol in this system involves three primary reactive species: hydroxyl radicals (•OH), sulfate radicals (•SO 4 − ), and singlet oxygen ( 1 O 2 ), among which 1 O 2 plays the dominant role. The coexistence of Cu and Fe species may facilitate surface redox reactions during PMS activation, while defect-related oxygen sites may contribute to PMS adsorption and activation and the generation of 1 O 2 . This study provides a novel strategy that enables the resource utilization of oil sludge while simultaneously addressing environmental remediation challenges.