Multifunctional porous nanofibrous membranes with superior antifouling properties for oil-water separation and photocatalytic degradation

The oily wastewater composed of complicated organic pollutants and bacteria showed a huge threat on the environment and humans. Currently, the membrane used to treat oily wastewater have the problems of cumbersome preparation, weak adhesion and metal leaching, and membrane pollution is also the focus of urgent problems. In this study, the metal-free chlorine-sulphur double-doped graphitic carbon nitride (Cl/S-g-C3N4) photocatalyst was incorporated into polyacrylonitrile (PAN) nanofibrous membrane via an electrospun method. The resultant porous nanofibrous membrane possessed the superior superhydrophilicity and superoleophobicity under water, ensuring a high separation efficiency (>98.0%) for various oil-in-water emulsions. Specially, the membrane achieved a superior self-cleaning property after visible light irradiation for crude oil/water mixture and actual oily wastewater with FRR up to 95%, which was related to the enhanced light absorption ability and the effective electron hole separation ability of Cl/S-g-C3N4. Moreover, the porous structure increased the possibility of contact between contaminants/bacteria and reactive species, beneficial to the photodegradation and antibacterial properties, achieving extremely high resistance to contamination. Overall, the multifunctionality of the porous anti-fouling nanofibrous membrane exhibited a huge potential in practical oily wastewater treatment.