Natural polymers-based separation membrane for high-efficient separation of oil water mixture

Abstract

In recent years, the problem of oil pollution represented by industrial oily waste occurs frequently, and the general hydrophilic filtration materials are facing the problems of clogging and poor hydrophilicity, so the hydrophilic hydrogel materials have received some attention, but the related research can’t balance the filtration materials related to the needs of high efficiency, rapidity and stability. In recent years, research on physically cross-linked hydrogels has been developed. We designed a hydrogel made of natural polymers and modified materials including cotton cloth and copper foam by coating or dip coating, and prepared physically crosslinked hydrogel-modified filtration materials, in which the pore size of 10 μm and a superhydrophilic/underwater superoleophilic wettability with an oil contact angle of more than 150° underwater can realize a water flux of more than 10⁶ L·m⁻²·h⁻¹ and an oil-water flux of more than 99 % efficiency. The oil-water separation efficiency higher than 99 %. Through the action of its ionic electrolyte, it can decompose emulsions containing different surfactants with an efficiency of more than 99 %, and it still possesses high hydrophilicity and separation efficiency even when immersed in pH=1 acid solution for 1 h, and it still possesses high water flux and separation efficiency even when abraded more than 100 times. The materials used are all non-toxic and are not harmful to the environment after segregation. The physically cross-linked hydrogel prepared in this experiment provides a method for realizing oily wastewater purification without secondary pollution, with high efficiency, rapidity and stability, and has a high potential for further development.