Highly chlorine and oily fouling tolerant membrane surface modifications by in situ polymerization of dopamine and poly (ethylene glycol) diacrylate for water treatment

Abstract

Here we show a simple hydrophilic-membrane surface modification method using in situ polymerization of aqueous dopamine and poly(ethylene glycol) diacrylate (PEGDA) mixture to improve both oily fouling and chemical resistance of membranes for water treatment. Polydopamine (PD) induced from aqueous dopamine solution has been extensively studied for facile membrane surface modification but the PD layer is very susceptible to chemical attack (e.g., sodium hypochlorite [NaClO]). To overcome this disadvantage, in this study, crosslinked poly(ethylene glycol) (XLPEG) chains were successfully introduced with PD layer using PEGDA with a thermal free radical initiator. As a result, the XLPEG/PD-coated membranes showed excellent chemical stability against chlorine attack as well as much improved oily fouling tolerant behavior, without any sacrifice of original water permeance, as compared with only PD-coated membranes. This surface modification method will be readily used for many membranes for water treatment from flat sheet to hollow fiber membrane modules.