Simple temperature-regulated polymerization for the fabrication of a tea polyphenols-modified PVDF membrane for emulsion separation

Surface modification of membranes through facile coating methods is a promising way to improve their pollution resistance and separation performance. Herein, a tea polyphenol (TP)-coated PVDF membrane (PVDF-TP) was prepared via a simple temperature-regulated oxidative polymerization. The obtained membrane exhibited a water contact angle of 0° and underwater oil contact angle of 168.2°. This superhydrophilic/underwater superoleophobic membrane showed good separation capabilities with fluxes of 88.3–169.9 L m−2 h−1 and separation efficiencies of over 98.7% for various oil-in-water emulsions under a gravity-driven process. The PVDF-TP membrane exhibited excellent stability and was capable of withstanding ultrasonic waves, bending, and agitation. Even after recycling for more than 15 times, the separation efficiency of the membrane was still above 98.7% and the flux decreased by approximately 37%, demonstrating a good antifouling performance. Considering the characteristics of its simple preparation, good antifouling performance, high separation efficiency, and good stability, the PVDF-TP membrane has broad application prospects in the field of oil–water separation.