Modified ceramic membrane with pH/ethanol induced switchable superwettability for antifouling separation of oil-in-acidic water emulsions

Nowadays, oily wastewater is a harmful pollutant to the environment. Membranes with switchable wettability have great advantages in the oil–water separation. Herein, a novel ceramic composite membrane with switchable superwettability is fabricated by combining a dopamine-assisted nanoparticle coating process and a chemical grafting of copolymers with responsive groups. FESEM, XPS, FTIR, TG and contact angle measurements confirm the success of each surface modification steps. The as-prepared membranes transform from superhydrophobicity in air to superhydrophilicity in acidic aqueous solution (pH = 1) and recover to superhydrophobicity after immersion in ethanol. This superhydrophobicity-superhydrophilicity translation can repeat cyclically. The superwettability switchable membranes can effectively separate oil–water mixture and emulsions. Furthermore, good antifouling property of the composite membrane in filtration of oil-in-acidic water emulsions (pH = 1) has also been obtained. All these results show that this kind of ceramic composite membranes would have important applications in oil pollution control and industrial wastewater treatment.