Superhydrophobic Bud Protrusion-Polypropylene Fiber Membrane with Ultrahigh Flux for Oil–Water Separation

To enhance oil–water separation efficiency, it is urgent to synthesize novel membrane materials that exhibit high flux and high retention efficiency and excellent antisolvent property. Herein, a seeding–extension–bud protrusion procedure was developed to fabricate superhydrophobic separation membranes through UV-assisted grafting and covalent modification on a microporous polypropylene. The synthesized superhydrophobic membranes (PPN-HDI-TPFOS) exhibit a bud protrusion micro/nanostructure, which significantly increases the contact area between the membrane surface and the emulsion, as well as the collision among the emulsion droplets during the oil–water separation. This membrane shows high flux of up to 24 800 L m–2 h–1 for dichloromethane (DCM)/water immiscible oil–water mixtures and 6528 L m–2 h–1 for water-in-DCM emulsions, together with excellent water retention (>99%) as well as good antisolvent property. Moreover, it exhibits excellent retention rates (>98%) for other water-in-oil emulsions (kerosene, hexane, and cyclohexane). This work supplies a useful strategy to synthesize complex membrane with extremely high flux as well as high rejection rate.