Design of Janus fabric membranes with asymmetric wettability and controllable pore size for on-demand separation of oily wastewater

Membrane separation materials with special wettability are progressively desired due to economy, high efficiency, and continuous operation. Among them, Janus membrane materials play an important role in controllable oil/water separation with the help of different wettability on each side. However, they still face various challenging problems, such as involvement of toxic chemicals, complexity of the modification process, and poor stability. In this study, based on the yarn functionalization and fabric structure design, double-layer Janus fabric membranes (JF membranes) with hydrophilicity and hydrophobicity were woven on each side of the membranes. The results showed that JF membranes achieved separation efficiency of 99.47 ± 0.35 % and 97.66 ± 0.53 % for light oil/water mixture and heavy oil/water mixture, and the separation flux exceeded 3008.5 L · m −2 · h −1 and 7161.04 L · m −2 · h −1 , respectively. Meanwhile, JF membranes can also separate oil-in-water emulsions (separation efficiency >96.33 %) and water-in-oil emulsions. In addition, JF membranes exhibit desirable chemical stability, mechanical durability and reusability. These results highlight the potential application of JF membranes with asymmetric wettability in oil-water separation and provide a novel, convenient, and feasible strategy for fabricating environmentally friendly membrane separation materials.