Combined Process of Integrating Fe(II)-Catalyzed Sodium Percarbonate Oxidation with Ceramic Membrane Filtration: Achieving Continuous Removal of Petroleum and Mitigation of Membrane Fouling

Washing oil, a petroleum product, is a mixture of naphthalene, fluorene, biphenyl, quinoline, pyridine, indole, and their substitutes. Emulsified washing oil wastewater contains small oil droplets that are stably dispersed in water, making oil recovery difficult. Therefore, advanced oxidation is used for removal, and a Fenton-like oxidation reaction using sodium percarbonate (SPC, Na2CO3·1.5H2O2) rather than hydrogen peroxide (H2O2) offers a safer alternative. In this study, Fe(II)-catalyzed SPC (Fe(II)/SPC) oxidation and ceramic membrane filtration were combined to achieve the continuous purification of emulsified washing oil wastewater. Fe(II) and SPC were injected at dosages of 144 and 96 mmol/h, respectively, and the washing oil removal efficiency from the 100 mg/L influent emulsion wastewater reached 98.77%. The significant reduction in total resistance indicated that the oxidation process effectively alleviated membrane fouling and enhanced the membrane’s reusability. Quinoline was selected as the target analyte in the washing oil emulsion, and its degradation pathways via Fenton-like oxidation were proposed. The findings of this study provide a reference for the research on advanced oxidation-coupled membrane filtration for petroleum wastewater treatment.