Fabrication of electro-neutral nanofiltration membranes at neutral pH with antifouling surface via interfacial polymerization from a novel zwitterionic amine monomer

A kind of novel electro-neutral nanofiltration (NF) membrane at neutral pH was fabricated by interfacial polymerization from a novel zwitterionic amine monomer PEI-g-SBMA. The zwitterionic amine endowed the resultant NF membrane with an electro-neutral separation layer under neutral condition and enhanced antifouling property via regulation of surface charge balance. The electro-neutral zwitterionic NF membranes (PEI-g-SBMA/TMC) showed a high water flux of 132   L/ (m 2   h   MPa), i.e. over 2 times higher than that of the PEI/TMC membranes without grafted SBMA. The PEI-g-SBMA/TMC membrane exhibited a high dye rejection (90.6% for Orange GII) but a low salt rejection (7.1% for NaCl and 50.4% for Na 2 SO 4 ). Meanwhile, the antifouling property against bovine serum albumin (BSA), sodium alginate (SA) and humic acid (HA) was significantly improved compared with the PEI/TMC membranes. The as-fabricated electro-neutral PEI-g-SBMA/TMC membranes with high organics rejection and low salt rejection as well as good antifouling property may find promising application potential in food, pharmaceutical, chemical industry and membrane bioreactor (MBR) processes.