An antifouling loose nanofiltration membrane prepared by cross-linking HPAN ultrafiltration membrane with zwitterionic polymer PEI-CA for efficient dye desalination

In this study, a novel antifouling loose nanofiltration (LNF) membrane was prepared by the cross-linking and grafting of hydrolyzed polyacrylonitrile ultrafiltration (HPAN UF) substrate with a polyethylenimine (PEI) based zwitterionic polymer PEI-CA through the covalent amide bond. The successful introduction of PEI-CA was verified by various techniques. The tailored membrane HPAN-PEICA exhibited ultra-high water permeance (73.5 L m−2 h−1 bar−1) and meanwhile maintained excellent rejection (~99.9 %) for dye Brilliant Blue R (BBR), Methyl Blue (MB), Congo red (CR) and Chrome Black T (CBT). In addition, it exhibited ultralow rejection (below ~6 %) towards the inorganic salts (NaCl, Na2SO4, MgCl2 and MgSO4), with excellent dye/salt selectivity of ~65. The as-fabricated membrane HPAN-PEICA was proved having good long-term operation stability and pressure resistance properties. Dynamic fouling experiments confirmed that the membrane HPAN-PEICA presented excellent antifouling performance towards four typical model foulants (LYZ, SA, HA and BSA). Over all, we believed that the tailored LNF membrane HPAN-PEICA having great application prospects in textile effluent treatment.