Climate-adaptive photothermal superhydrophobic CA/PU membrane for oil–water separation

Abstract

Within the realm of membrane separation technology, low temperatures can lead to an increase in oil viscosity and the freezing of water, resulting in a significant decline in separation efficiency. Herein, a climate-adaptive photothermal superhydrophobic membrane (CA/PU₃-PZ) was prepared through layer-by-layer assembly of polydopamine (PDA) coating and hydrophobic-modified ZIF-8 (ZIF-8-M) particles onto a cellulose acetate/polyurethane (CA/PU) electrospun membrane. The incorporation of PU into the CA matrix enhanced the tensile strength of the membrane from 0.14 MPa to 1 MPa. The CA/PU₃-PZ demonstrated exceptional oil–water separation performance. Notably, its separation capability can be fully restored to the original level within 10 minutes under light exposure, even after freezing at low temperatures. Furthermore, the CA/PU₃-PZ membrane exhibited outstanding anti-icing capability, with the freezing duration of droplets on its surface significantly prolonged to 981 s. This presented a streamlined, economically viable, and eco-friendly method for fabricating oil–water separation membrane materials that exhibited temperature adaptability.