Durable Electrospun Superhydrophobic Polyacrylonitrile/Polybenzoxazine Fibrous Membrane with High Flux for Efficient...

Oily wastewater discharge poses significant environmental challenges, while conventional polymeric membranes often suffer from poor mechanical stability during repeated operation. Herein, a durable superhydrophobic polyacrylonitrile/polybenzoxazine (PAN/PBOZ) fibrous membrane is developed via electrospinning, followed by thermal curing. Owing to the intrinsically low surface energy of polybenzoxazine and the formation of a rigid cross-linked network reinforced by Si-O-Si linkages and intermolecular hydrogen bonding, the membrane exhibits pronounced superhydrophobicity with a surface energy of 18.1 mN/m and a water contact angle (WCA) of 155.0 ± 2.4°. The optimized membrane demonstrates efficient gravity-driven oil-water separation, achieving an ultrahigh oil flux of 20,316 ± 1982.9 L·m^-2·h^-1 and a separation efficiency of 99.2 ± 0.45% for dichloromethane-water mixtures. Furthermore, the membrane exhibits exceptional long-term stability, maintaining high separation efficiencies over 40 consecutive cycles, alongside outstanding environmental and mechanical durability against continuous UV irradiation, extreme pH (1-13) conditions, and severe physical abrasion. The separation mechanism is governed by Laplace pressure, enabling rapid oil permeation and effective water rejection.