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.