Sulfonated Reverse Osmosis Membrane Fabricated with Comonomer Having Excellent Scaling and Fouling Resistance

Abstract

Silica scalant and organic foulant are rapidly deposited onto the surface of a thin-film composite (TFC) reverse osmosis (RO) membrane during the desalination process. The scaling and fouling propensity of the membranes are affected by the properties of the membrane surface. In this work, a sulfonated TFC-RO membrane was prepared with a comonomer of 2,5-diaminobenzenesulfonic acid (DABS) and m-phenylenediamine (MPD) through an interfacial polymerization process to promote the scaling and fouling resistance. Detailed characterization was carried out to analyze the structure and surface morphology of the fabricated TFC-RO membranes. Compared to the nascent PA TFC-RO membrane, PA-DABS membranes exhibited a smoother, negatively charged, and more hydrophilic surface and showed significantly lower flux decline in both silica scaling and combined scaling–fouling experiments. Moreover, gradient isosurfaces for the interaction indicated a sulfonic group having stronger repulsion with silicic acid than the carboxyl group. Therefore, this work provides new understanding of a simple and efficient design of RO membranes that can be used for desalination of combined mineral-silica and organic-fouling laden water.