Hierarchically stabilized PAN/β-FeOOH nanofibrous membrane for efficient water purification with excellent antifouling performance and robust solvent resistance

Filtration membranes, with good antifouling performance and robust solvent resistance (e.g., organic solvents or highly acidic/alkaline/saline solvents), that can effectively purify complex polluted water systems are especially demanded in practice but present a challenge to be conquered. Herein, a simple method has been demonstrated to address the obstacles, applying the stabilized polyacrylonitrile (SPAN) nanofiber/β-FeOOH nanorod composite membrane as a model. In this work, simply stabilizing PAN nanofibers in air can achieve robust solvent resistance against organic solvents and strong inorganic acidic/alkaline/saline solutions. Hydrophilic β-FeOOH nanorods were anchored onto SPAN nanofibers of our electrospun membrane and achieve superhydrophilicity (0°)/underwater superoleophobicity (>155°) for various oils. More importantly, the SPAN/β-FeOOH nanofibrous membrane exhibits robust mechanical strength (274 MPa of Young's modulus), excellent chemical stability, fast separation flux (2532-10146 L m-2 h-1), and satisfying removal ratio (>98.2%) against insoluble oils and soluble cationic dyes. In addition, good photocatalytic activity against organic pollutants provides our membranes with excellent flux restorability and a long-term use capacity. These outstanding performances endow our membrane with a great potential application in purifying polluted aquatic systems in worldly harsh conditions.