pH-responsive nanofibrous membrane with P(AA-r-MPS)/SiO2 hybrid hydrogel coating for oil-water separation

The ecological environment faces significant risks from oil-containing wastewater, highlighting a pressing need for advanced and effective oil-water separation methods. Although membrane separation technology is recognized for its low energy consumption, it faces challenges including low porosity and high cost in its traditional forms. Smart membranes, offer a new path to overcome this bottleneck. This study developed a pH-responsive PVDF oil-water separation membrane by preparing an organic-inorganic hybrid material through the hydrolytic hybridization of a copolymer containing a silane coupling agent with nano-SiO 2 . The smart separation membrane not only achieved a high oil-water rejection rate (>99.80%) and remarkable flux of 1821 L·m −2 ·h −1 , but also exhibited intelligent self-cleaning properties. Leveraging its pH responsiveness, simple rinsing with acidic water effectively removed contaminants, resulting in a flux recovery rate of up to 97.90%, highlighting its significant potential for treating complex oily wastewater. Collectively, these results demonstrated that this strategy has achieved a degree of integration between high-efficiency separation performance and intelligent self-cleaning functionality, providing valuable insights and potential solutions for the advancement of intelligent separation technology. • pH-responsive membrane made via in-situ crosslinking of P(AA-r-MPS) and nano-SiO 2 on PVDF. • M-HG/SiO 2 achieves >99.8% oil- water separation and 1821 L m -2 h -1 flux under acid. • M-HG/SiO 2 enables pH-triggered self-cleaning with 97.9% flux recovery after acid rinsing. • The hybrid coating provides stable underwater superoleophobicity over multiple cycles. • High efficiency (>99.2%) and structural stability are maintained in harsh pH environments.