Novel bifunctional MoS2@g-C3N4/polyacrylonitrile hybird porous nanofiber membranes for crude oil–water separation and p-nitrophenol degradation

The development of membrane separation technology has long been constrained by membrane fouling issues. This work developed novel chlorine sulfur double-doped graphite carbon nitride composite molybdenum disulfide photocatalyst (MoS2@Cl/S-TCN) and incorporated it into polyacrylonitrile nanofiber membranes through electrospinning technology to obtain porous catalytic nanofiber membrane (MoS2@Cl/S-CNM). MoS2@Cl/S-CNM has superior oil–water separation and photocatalytic degradation performance. The typical porous and nodular structures of nanofiber endow the membrane with superior hydrophilicity and lipophobicity under water. The MoS2@Cl/S-CNM exhibits superior oil–water separation efficiency above 98.0% for various oil-in-water emulsions including crude oil emulsion. Significantly, the composite membrane shows a superior self-cleaning performance with the flux recovery rate (FRR) of up to 96.1% for actual oilfield wastewater under visible light irradiation washing conditions. In addition, the novel MoS2@Cl/S-TCN catalyst, with a fast transfer of charge carriers at the interface, effective separation of photogenerated electron hole pairs and great thermodynamic driving force, renders the membrane with a positive photocatalytic degradation ability of 79.5% to p-nitrophenol (PNP). MoS2@Cl/S-CNM also exhibits excellent durability and chemical stability during various solvents and salt solutions. In conclusion, the novel multifunctional catalytic membrane is of great significance for the advanced treatment of petroleum industry wastewater in terms of severe membrane fouling and complicated wastewater quality conditions.