Fabrication and properties of asymmetric PET fabrics with high-permeation flux for on-demand oil/water separation

Indeed, it is yet to be achieved that finds a viable solution to the challenge of ever-growing and severe oil wastewater issues to meet easy operation and low cost. Herein, a facile strategy was proposed to fabricate asymmetric membranes via immobilizing poly (itaconic anhydride) (PITA) super-hydrophilic polymeric nanoparticles onto the surface of polyethylene glycol terephthalate (PET) nonwoven fabrics (PET-g-ITA) by surface precipitation photo-grafting (S2P) polymerization under ultraviolet (UV) light. The PET-g-ITA membrane displayed in an asymmetry mode mainly attributed to the UV shield feature of PET. Subsequently, the asymmetric PET-g-ITA membrane was hydrolyzed in an alkaline solution to enable the UV-illuminated side with superior hydrophilicity (WCA∼0°) and underwater superoleophobicity (UOCA∼153°). It exhibited outstanding performance in the selective separation of water and light/heavy oil. In water removal mode, the water/n-hexane mixture exhibited notably high permeation flux (94,562 ± 4948 L m-2 h-1) and high separation efficiency (99.8 %) for water. Meanwhile, the water/dichloromethane mixture also showed remarkably high permeation flux (76,238 ± 8949 L m-2 h-1) and separation efficiency (94.5 %) for dichloromethane in oil removal mode. More interestingly, these membranes could almost restore their oil/water performance to that of the primary membrane after cleaning. All separation processes are handled by energy-efficient gravity-driven separation methods, providing a competitive route for on-demand water and light/heavy oil separation.