An electrospun iron oxychloride/polyacrylonitrile nanofibrous membrane with superhydrophilic and excellent regeneration properties: Achieving superior oil-in-water emulsion separation

Superhydrophilic polymer membranes are widely used in oil-water separation due to their excellent wettability, high efficiency, low cost, and good biocompatibility. However, challenges such as fouling adhesion and inadequate stability persist during the treatment of oily wastewater. Herein, a novel iron oxychloride/polyacrylonitrile (FeOCl/PAN) nanofibrous membrane with superhydrophilicity and remarkable regenerability was successfully fabricated through simple electrospinning technique, which maintained good physicochemical stability under various harsh conditions with the uniform distribution of FeOCl on PAN fibers. The surface morphology and chemical compositions of the optimized FeOCl/PAN membrane were studied by several characterization techniques. The introduced FeOCl nanocrystals through electrospinning endowed the membrane with a rougher surface structure, significantly improving the hydrophilicity of the FeOCl/PAN nanofibrous membrane. In the cross-flow isooctane-in-water emulsion separation experiment, the initial water flux recovery rate (FRR) of the membrane increased from 92 % for the pure PAN membrane to around 99 %. Meanwhile, the optimized FeOCl/PAN nanofibrous membrane achieved an emulsion (isooctane) flux of approximately 632.9 L m−2 h−1, with an oil droplet removal rate surpassing 99.4 %. Furthermore, by cleaning the membrane with H2O2 (60 mM, pH = 3), the FeOCl/PAN membrane exhibited an exceptionally high water flux recovery rate (∼100 %) after high-concentration paraffin-in-water emulsion (4000 mg L−1) separation. In addition, the FeOCl/PAN membrane also demonstrated excellent antifouling performance in bovine serum albumin (BSA) pollution experiment. In summary, this work might provide a unique strategy for preparing advanced functional membranes with superior efficiency and durability for emulsified oily wastewater treatment.