Silica-Nanocoated Membranes with Enhanced Stability and Antifouling Performance for Oil-Water Emulsion Separation

Despite the potential of glass fiber (GF) membranes for oil-water emulsion separations, efficient surface modification methods to enhance fouling resistance while preserving membrane performance and stability remain lacking. We report a silica nanocoating method to modify GF membranes through a vapor deposition method. The high smoothness (<1 nm r.m.s.) and high conformality of the vapor-deposited silica nanocoatings enabled the preservation of membrane microstructure and permeability, which, combined with the enhanced surface hydrophilicity, led to an oil rejection rate exceeding 99% and more than a 40% improvement in permeate flux in oil-water emulsion separations. Furthermore, the silica nanocoatings provided the membranes with excellent wet strength and stability against organic solvents, strong acids, oxidants, boiling, and sonication. The silica-nanocoated membrane demonstrated enhanced fouling resistance, achieving flux recovery higher than 75% during repeated oil-water emulsion separations and bovine serum albumin and humic acid fouling tests.