Self-cleaning PDA-Ag@PVDF membranes for oil/water separation and dye adsorption from emulsion

Abstract

Membrane separation technology, as an important means of treating oily wastewater, is considered to be one of the most promising oil/water separation technologies. However, problems such as membrane contamination and single separation performance have also hindered its wider application. In this study, polydopamine (PDA)-Ag nanospheres were prepared by oxidant-induced dopamine polymerization and in situ reduction with silver ions, and assembled onto silanized poly(vinylidene fluoride) (PVDF) filtration membranes by a vacuum-assisted operation. The separation efficiency of the PDA–Ag@PVDF filter membrane for the dichloroethane oil-in-water emulsion was 98.8%, and the removal rate of malachite green dye in the emulsion was as high as 98%. After multiple separation/UV irradiation cycles, the flux recovery rate was greater than 98.7%. The PDA–Ag@PVDF filter membrane is a multifunctional and self-cleaning separation membrane, whose excellent properties make it promising in the field of oil/water separation.