The nanofiltration membrane was modified with a thermo-responsive polymer.The fouling control mechanism of the thermo-responsive nanofiltration membrane under non-phase transition conditions was investigated.The results showed that the polyamide layer of the thermo-responsive nanofiltration membrane had a low cross-linking degree and a relatively thin thickness.The pure water flux of the modified nanofiltration membrane was increased by 71％to that of the pristine nanofiltration membrane.The rejection rate of divalent anions was over 97％,while the re-jection rate of monovalent anions slightly decreased.Through the dynamic fouling test,the nor-malized flux of the modified nanofiltration membrane increased by 8.4％compared with the pris-tine nanofiltration membrane.Molecular dynamics simulation showed that the polyamide layer lost protons in the aqueous solution.The electronegative polyamide layer could adsorb calcium ions through electrostatic interaction,forming a composite fouling between"membrane-cation-organic matter".The thermo-responsive polymer was electrically neutral and was far from the cations,which suppressed membrane fouling caused by bridging.
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