Development of alginate hydrogel modified multifunctional filtration membrane with robust anti-fouling property for efficient water purification

Abstract

Anti-fouling behavior of separation membranes has attracted continuous interest. In particular, crude oil is easy to adhere to many surfaces owing to its high adhesive characteristic, and the issue of treatment of crude oil-in-water emulsion is a challenge. Hydrogel modified composite has the robust potential to deal with crude oil-in-water waste, and the critical issue is the development of a hydrogel layer with controllable thickness and micro- and nanosized membrane pores. Thus, novel separation composite membrane derived from porous Ca2+/alginate hydrogel thin film on commercial filter paper supporting substrate (alginate@FP) was fabricated via freeze drying and subsequent in-situ gelation. Furthermore, SEM, FT-IR, EDS and contact angle tests were used to characterize the physical and chemical properties of the composite membranes, and the permeance and rejection ability of the as-prepared filtration membranes were determined. As a result, the alginate@FP behaves an excellent superhydrophilicity, underwater superoleophobicity, anti-crude oil-fouling performance and self-cleaning effect. Besides, with controllable thickness and surface morphology, both the high flux and efficient emulsion separation were well-obtained. At the same time, it exhibits good reusability, and is stable in kinds of chemical environments. On the other hand, due to the negatively charged membrane surface, soluble dyes and some metal ions can also be removed with a high efficiency through filtration, simultaneously.