Engineering self-rebound catalytic membranes for efficient high-viscosity oily wastewater purification and emerging contaminants removal

Abstract

Separation membranes with high antifouling and self-cleaning capabilities are vital for long-term operation during practical high-viscosity fluid purification. Herein, we report an oil-rebound catalytic self-cleaning membrane constructed via a synergistic in situ reduction–coordination synthesis strategy. A hydrogen-bonded hydrogel of tea polyphenol/polyvinylpyrrolidone reduces and coordinates silver ions into an ultrathin hydrated Ag nanocoating at the membrane interface, providing a facile and robust route for directional nanoparticle loading. The membrane exhibited ultrahigh permeance for isooctane-in-water emulsion (>8800 L·m^-2·h^-1·bar^-1) and remarkable antifouling stability (>99.9% rejection over multiple cycles, apart from ethanol and pH = 1 acid). When processing challenging emulsified high-viscosity oily wastewater, the engineered superwetting interface prevents oil adhesion due to a unique oil-rebound antifouling mechanism, maintaining consistently high permeance (>1000 L·m^-2·h^-1·bar^-1 over 1 h). Notably, even under severe fouling conditions, the membrane maintains excellent regenerability, achieving 99.8% permeance recovery through efficient peroxymonosulfate (PMS)-activated catalytic cleaning towards various contaminants. This work demonstrates a facile biomimetic design strategy for advanced membranes in challenging separation scenarios.