Synthesis of Ambient Copolymerization CQAS Hydrogel Composite Membrane with Enhanced Antifouling

Abstract Hydrogel molecular structure contained massive hydrophilic groups, which can capture water molecules to form the rejection layer of natural organic matter (NOM). Aiming at introducing the excellent properties of hydrogels into the water treatment separation membrane, a new kind of positive charged ambient self‐crosslinking chitosan quaternary ammonium salt (CQAS) hydrogel is designed and applied to prepare a hydrogel composite membrane via surface coating method. Effects of the amount of initiator on the ambient self‐cross‐linking time of CQAS hydrogels is discussed, as well as the impacts of coating amount of ambient self‐cross‐linking CQAS pre‐gel solution on the comprehensive properties of the composite membranes is also studied. The membrane structure and morphology is characterized by FT‐IR, FE‐SEM, AFM, and the membrane properties are evaluated by dynamic contact angle and membrane performance evaluation instrument. The obtained CQAS hydrogel composite membrane exhibited super hydrophilicity, high, and stable separation performance of monovalent and divalent cations, excellent long‐term tolerance, and resistance to NOM contaminants. Specifically, in the dynamic antifouling test, the stable flux recovery rate of the CQAS hydrogel membrane to the simulative contaminants BSA, HA, and SA are 82.95%, 92.89%, and 73.37%, respectively.