One-step fabrication of robust Stenocara beetle-inspired membrane deriving from polyethylene terephthalate (PET) waste for enhancing emulsion separation

The purification of emulsified water from waste oil has become a major research topic. Stenocara beetle-inspired wettable membranes have emerged as separating-efficient designs for purification of oil due to surface energy difference and surface roughness driven demulsification, but they are still suffering from tedious preparation and low robustness. Herein, a one-step electrospinning/electrospraying process was employed to construct Stenocara beetle-like membrane using waste PET and tetrabutyl titanate (TBT) as raw materials for water-in-oil emulsion separation. Specifically, the synchronized deposition process combines electrospinning high-hydrophobic PET fiber membrane and electrospraying superhydrophilic TiO 2 particles (superhydrophilic bumps) generated from hydrolysis of TBT on the PET membrane surface, leading to a similar structure to Stenocara beetle. During the separation process, the bumpy superhydrophilic TiO 2 particles can capture and aggregate tiny water droplets even though the droplet size is smaller than the membrane pore size. Moreover, this Stenocara beetle-like structure exists both on the surface and interior of the samples, resulting in the boosted demulsification ability and excellent separation efficiency up to 99.8 % and flux as high as 6392 L m -2 h −1 . Stenocara beetle-like membrane also exhibits strong mechanical properties and strain of the membrane is up to 128.8 %. Even after the friction test, the membrane maintained cycling stability and abrasion resistance with separation flux higher than 3500 L m -2 h −1 . Overall, this efficient one-step strategy can open up new avenues to fabricate advanced superwetting membranes in the field of emulsion separation.