Binary fiber membranes with dual transport channels and interfacial demulsification for continuous emulsion separation

Membrane fouling occurred during subsequent filtration weakens the application advantages of membrane separation technology in treating oil–water emulsions. Herein, a functionalized binary fiber membrane with dual transport channels and enhanced interfacial demulsification was fabricated for facilitating continuous emulsion separation. The interpenetrated cellulose acetate (CA) and polytetrafluoroethylene (PVDF) fibers offer independent channels for transferring water and oil in the binary fiber membrane, which enables the timely removal of the continuous oil contamination to mitigate membrane fouling. Moreover, a Span 80 functional layer assembled on the binary fiber membrane by a solvent-induced grafting approach promotes dynamic interfacial demulsification and antifouling of membrane materials. Owing to the advantages of dual oil–water transport channel and Span 80 functional demulsification layer, the binary fiber membrane can separate continuously emulsifier-stabilized oil-in-water emulsions. Consequently, the binary fiber membrane can handle emulsions with high oil content (>5 vol%), and a single-stage separation time can last up to 5 h with a separation efficiency of over 98 %, because of its dynamic antifouling properties. Significantly, the membrane exhibits desirable cycling performance, and the Span 80 functional layer can be easily assembled to reset the separation performance, which encourages continuous emulsion separation and an extended membrane service life. Overall, this work opens a new avenue to fabricate binary fiber membranes with dual transport channels for sustainable antifouling and continuous emulsion separation, with high potential in practical applications relating to oily wastewater treatment and fuel purification.