Preparation of super hydrophilic-underwater super oleophobic photoinduced self-cleaning Al2O3 @TiO2 ceramic membrane and separation performance of oil-in-water emulsion

Membrane hydrodynamic irreversible oil fouling is a pressing issue. Here, an antifouling Al2O3 @TiO2 membrane with excellent wettability was created using the sol-gel method to create an anatase nano-TiO2 coating on the surface of an Al2O3 ceramic membrane. Analyzing the separation performance of an Al2O3 @TiO2 membrane on simulated oily emulsions determined the amount of TiO2 covered on the membrane surface (0.8 mol·L−1). Under the synergy of hydrophilic nano-TiO2 and ultraviolet (UV) light, the Al2O3 @TiO2 membrane demonstrated improved wettability and self-cleaning ability and maintained favorable separation performance (769.23 L·m−2·h−1, 97.75%, 1.23 mg·L−1) after 6 h of continuous separation of the actual oilfield produced water. After 30 min of UV illumination, the membrane flux recovered completely. This is due to the fact that the active substances (eg.,·OH,·O2, and 1O2) generated in situ on TiO2 on the membrane surface after UV illumination weakened the interaction of membrane surface fouling, resulting in less oil fouling. In addition, the Al2O3 @TiO2 membrane maintained extremely outstanding oil resistance stability and recoverability during high-intensity hydraulic flushing and 25 cycles of testing. This study provides a theoretical basis for the engineering application of ceramic membranes in oilfield-produced water treatment.