Sacrifice Template Strategy to the Fabrication of a Self-Cleaning Nanofibrous Membrane for Efficient Crude Oil-in-Water Emulsion Separation with High Flux

The superhydrophilic/underwater superoleophobic membrane materials have attracted considerable attention in oil/water separation. However, most materials are extremely susceptible to pollution during oil-water separation, which drastically restricts their widespread applications. Herein, a momordica-charantia-like nanofibrous membrane (MCNM) with underwater superoleophobic performance was fabricated through a sacrifice template strategy by the electrospinning solution of zeolitic imidazolate framework-8 (ZIF-8) and polyacrylonitrile particles. The opened voids and wrinkles left after removing the template of nanocrystals ZIF-8 not only increased the porosity and roughness of the as-prepared fibrous membrane but also tremendously improved the underwater superoleophobicity. Therefore, the as-prepared MCNM showed excellent self-cleaning performance toward crude oil under water, avoiding the decrease of the separation efficiency and flux caused by membrane fouling during oil-water separation. Meanwhile, the separation efficiency of various surfactant-stabilized oil-in-water emulsions was higher than 99.6% with a flux up to 1580 +/- 30 L m(-2) h(-1) solely driven by gravity. Moreover, no obvious wrinkles and cracks were observed on the resulted nanofibrous membrane after the sand impact and bent testing. More importantly, the asprepared MCNM still maintained exceptional underwater superoleophobicity in harsh environment (3.5 wt % NaCl, 4 M HCl, 50 degrees C hot water) even after ultrasound for 1 h. The robust mechanical and chemical stability makes the antifouling MCNM exhibit tremendous potential for practical applications in dealing with oily wastewater in the future.