Fast reversible ethanol response membrane for smart controllable oil–water separation application

Oil-water separation membranes with the merits of low energy consumption and high efficiency, have played an irreplaceable role in both industrial wastewater treatment and oil purification. Nevertheless, the simple preparation of an intelligent responsive membrane with rapid cyclic response, non-toxicity, and high efficiency remains a substantial challenge. In this paper, the material with ethanol-induced wettability conversion was prepared by hydrothermal and impregnation methods. Notably, the material can rapidly switch between superhydrophobicity and superhydrophilicity in less than 2 min, with more than 10 cycles of reversibility. The reasons have been insightfully revealed for the changes in the wettability of the membrane through surface energy physical parameters. Significantly, various oil–water mixtures were separated with high efficiency (99.7 %) and high flux (3.46 × 10 4 L·m −2 ·h −1 ) by gravity alone before and after the membrane wettability transition. In addition, the material exhibited excellent durability (more than 10 times), chemical and mechanical stability. This controllable wettability surface with the advantages of easy preparation, low cost, fast reversible response, wear resistance and durability, being expected to play an essential role in on-demand oil–water separation applications.