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

Tungsten trioxide (WO3) and titanium dioxide (TiO2) decorated commercial stainless steel meshes (SSM 304) were fabricated by chemical deposition and dip coating. WO3 and TiO2 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 WO3/TiO2 coatings were demonstrated for high oil rejection, stable underwater superoleophobic properties after abrasion treatment and steady water permeation flux after several cycles.