Selective Wettability and Pore-Size Exclusion Synergistic Membrane for Efficient Oil–Water Separation

Offshore oil spills and oily wastewater cause severe water pollution. Membrane separation offers a promising solution for efficient oil–water separation; however, conventional membranes often exhibit poor fouling resistance and face a trade-off between flux and separation efficiency due to mismatched pore sizes. To overcome these challenges, we developed a hydrolyzed polyacrylonitrile by tetraethyl orthosilicate modification (HPANT) nanofibrous membrane based on the synergistic mechanism of selective wettability and pore-size exclusion. And it achieves superhydrophilicity and underwater superoleophobicity, with the pore size regulated to ∼20 nm. This design achieves excellent fouling resistance and separation efficiencies of 98.29% for immiscible mixtures and 97.80% for surfactant-stabilized emulsions, with high fluxes of 6,941.5 L·L·m –2 ·h –1 ·bar –1 and 8,379.6 L·m –2 ·h –1 ·bar –1, respectively. Multiscale simulations (DFT, MD, FEM) further clarify the dual mechanism: the stable hydration layer resisting oil adhesion and tailored nanopores providing a physical barrier. This strategy provides guidance for the development of oil–water separation membranes.