Bio-fouling is a major issue in all membrane-based water treatment systems and there are several cleaning methods available to address this problem. Current membrane modification methods are focused on improving the hydrophilicity of membranes by blending hydrophilic additives or blending antibacterial compounds with the dope solution. In this study, we demonstrate a new method to impart bio-fouling resistance to a membrane surface by developing a water-insoluble unique copolymer additive, namely poly (acrylonitrile co maleic acid co di-amino maleio-nitrile) (PANCMACDAMN) with highly hydrophilic carboxylic and amine functional groups. Hydrophilic polyethylene glycol functionalized with silver (Ag) was grafted to the copolymer backbone to further improve the hydrophilicity. The final additive PEG-Ag attached PANCMACDAMN was used to modify polyethersulfone (PES) ultrafiltration (UF) membrane. Characterization tests indicate that the innovative surface chemistry increases the hydrophilicity of the membrane by reducing the water contact angle (CAw) by 78.1% and increases its permeability by 120% compared to the control membrane. More importantly, the innovative surface chemistry prevents protein attachment and exhibits inhibition to microbes even after 720 min of continuous protein solution filtration.

Graphical Abstract

Highly hydrophilic copolymer based PES hollow fibre ultrafiltration membranes