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.
Wáng et al. (Fri,) studied this question.