Eco-friendly WBF/PAN nanofiber composite membrane for efficient separation various surfactant-stabilized oil-in-water emulsions

The development of superhydrophilic and underwater superoleophobic membranes has brought promising prospect for solving severe environmental pollution caused by oily wastewater. However, most of such membranes cannot be widely used in practical oily wastewater treatment due to their harmfulness to environment and expensive price. Herein, an eco-friendly and economical nanofiber composite membrane was designed and fabricated by electrospinning strategy. The mixed solutions of waste bamboo fiber (WBF) and polyacrylonitrile (PAN) particles were electrospun on stainless steel mesh. It was found that the WBF/PAN nanofiber composite membrane possessed excellent underwater superoleophobic performance and ultralow oil adhesion ability. Particularly, the as-prepared membrane can selectively separate water from various surfactant-stabilized oil-in-water emulsions including high viscosity crude oil-in-water emulsions with high separation efficiency (> 99.3%) driven by only gravity. Furthermore, the WBF/PAN membrane maintained exceptional underwater superoleophobicity in the harsh environments (3.5 wt % NaCl, 0.1 M HCl, 0.1 M NaOH) even after being immersed into a corrosive solution for 24 h. Meanwhile, the membrane also showed excellent chemical stability after 10 separation cycles and robust mechanical stability after 50 times of abrasion test. More importantly, the eco-friendly and low-cost WBF/PAN nanofiber composite membrane conforms to the environmental protection concept of waste recycling and green sustainable development, which would be a competitive alternative for crude oil leakage and oily wastewater purification.