PVDF-based nanofiber membrane decorated with Z-scheme TiO2/MIL-100(Fe) heterojunction for efficient oil/water emulsion separation and dye photocatalytic degradation

Membrane separation is one of the most widely used methods for water purification, but membrane fouling is a stumbling block that must be overcome for its further promotion and application. In this work, a self-cleaning PVDF-based hybrid nanofiber membrane with core-sheath structure were constructed via electrospinning and in-situ synthesis, using polyvinylidene fluoride/polyvinyl pyrrolidone (PVDF-PVP) electrospun nanofibers as skeleton cores and in-situ synthesis of Z-scheme TiO2/MIL-100(Fe) heterojunctions as photocatalytic sheaths. The hybrid membrane exhibited excellent superhydrophilicity (water contact angle of 0°) and underwater superoleophobicity (underwater oil contact angle of 161.4°) with high permeate fluxes and superior separation efficiencies (more than 99.5%) for various oil/water emulsions. Furthermore, the Z-scheme TiO2/MIL-100(Fe) heterojunctions anchored on the nanofibers possessed robust photocatalytic activity with the removal efficiency of dyes up to 99.9% under simulated sunlight. More importantly, the membrane has excellent recyclability due to its outstanding anti-fouling and self-cleaning properties. Therefore, the hybrid membrane has attractive potential application in wastewater purification.