Swelling Poly(ionic liquid) Supported by Three-Dimensional Wire Mesh for Oil/Water Separation

A kind of oil/water separation membrane, combining poly(ionic liquid) (PIL) and three-dimensional (3D) wire mesh, was designed and prepared via one-step photopolymerization of an ionic liquid monomer 1,8-triethylene glycoldiyl-3,3'-divinylimidazolium dibromide ([DVIm-(EG)₃]Br₂) with acrylic acid in the mesh. The composite membrane (PIL@Mesh) had the advantages of anti-oil-adhesion property and high mechanical strength simultaneously. The morphology of PIL@Mesh characterized by scanning electron microscopy (SEM) and Cryo-SEM demonstrated that PIL swelled in water to construct microscale 3D networks. The 3D networks of swelling PIL were capable of forming a hydration layer and endowed PIL@Mesh with superhydrophilicity, which made the membrane to transport water but to intercept oil. PIL@Mesh showed excellent separation efficiency (above 99.9%) for various oil/water mixtures, large water flux (47 L·m^-2·s^-1), and high intrusion pressure (1.2 kPa). Meanwhile, it performed well in recyclability and corrosion-resistant under harsh conditions, such as acid, alkaline, and salty environments.