Waste PET derived Janus fibrous membrane for efficient oil/water emulsions separation

Effective treatment of diversified and complicated oily wastewater is of great significance but remains chal-lenging, Janus membrane with asymmetric wettabilities is an urgent need in the field of ideal oil-water sepa-ration. Herein, this work presents a facile and versatile method to fabricate polydopamine/polyethylene terephthalate/polyvinylidene fluoride (PDA/PET/PVDF) Janus membrane via sequential electrospinning tech-nique and surface chemical modification. Specifically, the PDA/PET side of the resultant Janus membrane possesses superhydrophilic/underwater superoleophobic properties and the PVDF side of Janus membrane exhibited hydrophobic/superoleophilic surface. It is indicated that the resulting asymmetric wettability of Janus membrane is controlled only by reversal, and the membrane can work as water/oil-removing material for on -demand emulsion separation. In addition, the as-obtained Janus membrane preserved asymmetric wettability for highly efficient separation of various oil-in-water emulsions (separation efficiency of 99.7 % and separation flux of 1,770 L.m(-2).h(-1)) and water-in-oil emulsions (separation efficiency of 99.5 % and separation flux of 19,200 L.m(-2).h(-1)bar(-1)). Furthermore, the Janus PET membrane also showed excellent mechanical property and good antifouling activity against contaminants due to the hierarchical porous structure. The waste-derived PET Janus fibrous membranes with mild fabrication processes show prominent separation efficiency, excellent mechanical property and good antifouling activity, which is of great importance for providing a flexible strategy to fabricate Janus membranes by using waste plastic as raw materials, as well as demonstrating a solution for multifunctional oil/water separation and purification.