Mechanistic insights into enhancing water transport and antifouling performance under high concentration polarization in polyamide membranes

Abstract

Reverse osmosis (RO)-based polyamide (PA) membranes encounter significant challenges in maintaining water transport efficiency and antifouling capability under high-salinity levels. Although self-assembled monolayer hydrophilic coatings based on polyethylene glycol (PEG) and its derivatives enhance performance at low salinity, their effectiveness diminishes in high-salinity environments. In this study, we employ molecular dynamics simulations to explore a novel modification strategy that integrates poly (ethylene glycol) diacrylate (PEGDA) as a hydrophilic polymer matrix with N,N′-methylenebis (acrylamide) (MBAA) as the mechanical bridge. This approach forms a robust PEGDA-MBAA nanoporous network on PA membranes, which, in comparison to conventional PEG coatings, better preserves hydration, maintains structural integrity, and exhibits enhanced resistance to humic acid fouling across varying salinity levels. These molecular-level insights into salinity-dependent water transport and fouling mechanisms offer a promising pathway for the design of next-generation, high-salinity, low-energy PA membranes for water treatment applications.