Sustainable photocatalytic‐membrane reactors for petroleum refinery wastewater remediation as a hybrid system

Abstract BACKGROUND Petroleum refinery wastewater (PRW) contains high concentrations of oil and organic pollutants, requiring efficient and sustainable treatment technologies. Hybrid photocatalytic membrane reactors (PMRs) have attracted increased attention due to their ability to combine advanced oxidation with membrane separation. This study develops a PMR incorporating a green calcium oxide (CaO) photocatalyst synthesized from tomato plant waste and a polyacrylonitrile (PAN) membrane for PRW treatment. RESULTS The PAN membrane was fabricated using the phase inversion technique and integrated with the green CaO photocatalyst under light‐emitting diode (LED) irradiation at a transmembrane pressure of 1 bar. The effects of CaO dosage (0–0.1 g/ L −1 ), reaction time (15–180 min), and initial oil concentration (10–1000 ppm) on oil and chemical oxygen demand (COD) removal were systematically evaluated. The PMR achieved a stable permeate flux of 69.19 L m −2 h −1 during PRW treatment. Complete oil removal (100%) and COD removal of 99.89% were obtained at initial concentrations of 1000 ppm oil and 2829 ppm COD, respectively, while removal efficiencies of 97.00% (oil) and 94.00% (COD) were obtained at lower pollutant loadings. The PAN membrane exhibited excellent antifouling and self‐cleaning behavior, with a flux recovery ratio of 96.60% at 100 ppm oil concentration. CONCLUSION The developed photocatalytic membrane reactor (PMR) demonstrated high treatment efficiency and operational stability for petroleum refinery wastewater (PRW). The synergistic interaction between the green CaO photocatalyst and polyacrylonitrile (PAN) membrane enhanced organic degradation and mitigated membrane fouling, producing effluents that comply with World Health Organization (WHO) discharge limits. The proposed system represents a promising, sustainable approach for advanced industrial wastewater treatment within chemical and biochemical engineering applications. © 2026 Society of Chemical Industry (SCI).