Bubble‐Mediated Active‐Passive Synergistic Antifouling Strategy and Dynamic Mechanism in Membrane Separation of Viscous Crude Oil Emulsions

ABSTRACT The gradual accumulation and deposition of oil on membrane surfaces during the oil‐water separation process causes the inevitable decline of membrane separation performance, highlighting the urgent demand for developing efficient and cost‐saving membrane fouling mitigation strategies. In this study, manganese dioxide (MnO 2 ) nanowires were blended with microfibril cellulose (MFC) to fabricate the MnO 2 /MFC (MM) membrane, and sodium alginate/polyvinyl alcohol (Alg/PVA) hydrogel layer was deposited onto the MM membrane surface by freezing and salting‐out strategy to prepare the Alg/PVA/MnO 2 /MFC (APMM) membrane. The hydrogel‐derived hydration layer endows APMM membrane with low underwater crude oil adhesion (0.73 µN) and high oil‐water selectivity (emulsion separation efficiency >99.23%). Based on the MnO 2 ‐catalyzed decomposition of H 2 O 2 solution, the in situ constructed microbubbles by the APMM membrane exhibit active oil‐repellent behavior, with a high permeance recovery of 91.6%. Importantly, the interfacial interaction between APMM membrane and foulants, and the microscopic process of oil droplet detachment from membrane pores are systematically clarified. By integrating hydrogel passive antifouling and bubble‐mediated active antifouling, the dual‐mode antifouling system demonstrates significant advantages in mitigating membrane fouling, offering a promising strategy for constructing novel antifouling membranes for efficient and energy‐saving oily wastewater treatment.