Tailored thin film nanocomposite membrane incorporated with Noria for simultaneously overcoming the permeability-selectivity trade-off and the membrane fouling in nanofiltration process

Membrane fouling as well as the “trade-off effect” between water permeability and selectivity are the grand challenges for nanofiltration (NF) membranes. In this study, a macrocyclic molecule, Noria, was embedded in the polyamide layer to fabricate a thin film nanocomposite (TFN) membrane with high performances of separation and antifouling. Noria was first synthesized and dissolved in a piperazine (PIP) aqueous solution. Then the TFN membrane (i.e., PIP-Noria-TMC membrane, TMC is the abbreviation of 1,3,5-benzenetricarbonyl trichloride) was prepared by interfacial polymerization using PIP-Noria mixture as aqueous phase. The optimal PIP-Noria-TMC membrane reached 147.6 L m^-2h^-1MPa^-1 of water permeability, which was almost twice that of the pristine NF membrane (i.e., PIP-TMC membrane). Meanwhile, the PIP-Noria-TMC membrane exhibited comparable Na₂SO₄ rejection (∼98%) to the PIP-TMC membrane and outstanding mono/divalent salt selectivity. Besides, static adsorption tests using E.coli and bovine serum albumin (BSA) as the model foulants revealed that the surface of PIP-Noria-TMC membranes with high hydrophilicity and electronegative charge could effectively resist foulant attachment, which was also exhibited in the dynamic BSA filtration tests. Therefore, this work provided a practicable pathway to simultaneously overcome the permeability-selectivity trade-off and membrane fouling problems for the NF process.