WO3/TiO2 superhydrophilic and underwater superoleophobic membrane for effective separation of oil-in-water emulsions

Abstract Tungsten trioxide (WO 3 ) and titanium dioxide (TiO 2 ) decorated commercial stainless steel meshes (SSM 304) were fabricated by chemical deposition and dip coating. WO 3 and TiO 2 particles were firmly and uniformly coated on the membrane surfaces, forming rough micro-nano double structures with underwater superoleophobicity, large contact angles and low oil-adhesion characteristic. Furthermore, the as-prepared membranes achieved effective oil-in-water (O/W) emulsions separation with high efficiency up to 98.5% or more. The separation of O/W emulsions was easily implemented under gravity with water fluxes of >200 L m −2  h −1 or low pressure with water fluxes up to 1300 L m −2  h −1 or more. In addition, the superhydrophilic membranes with WO 3 /TiO 2 coatings were demonstrated for high oil rejection, stable underwater superoleophobic properties after abrasion treatment and steady water permeation flux after several cycles.