A novel superhydrophilic hyperbranched polysiloxane grafted membrane for oil-in-water emulsion separation

Oily wastewater, posing serious environmental and social issues, has aroused widespread concerns. Membrane separation is regarded as an excellent candidate to solve the problem of oily wastewater, although membrane pollution is inevitable in the process of separation. The construction of hydrophilic surface reported so far can effectively mitigate membrane pollution. Herein, we reported a novel hyperbranched polysiloxane grafted polyvinylidene fluoride membrane (HBPSi-g-PVDF), which was prepared through grafting amino-terminated hyperbranched polysiloxanes onto the PVDF membrane surface via an amidation reaction. The HBPSi-g-PVDF membrane possessed superhydrophilic/underwater superoleophobic properties and excellent resistance to oil droplet adhesion. Meanwhile, the resulting membrane presented favorable water permeance (16924 L∙m-2∙h-1∙bar-1) and permeance recovery ratio (99.0%). In addition, the HBPSi-g-PVDF membrane displayed satisfactory separation efficiency (>99.1%) for diverse oil-in-water emulsions having over 6000 L∙m-2∙h-1∙bar-1 permeance. Furthermore, HBPSi-g-PVDF membrane also showed excellent environmental durability and recyclability, maintaining stable performance in hash environments, highlighting its great future for the disposal of oily wastewater.