Molecularly microporous polyarylate-polyamide nanofiltration membrane patched by tris(2-aminoethyl)amine for ionic sieving

Macrocyclic molecules with intramolecular cavities have shown great potential in membrane science. However, the nanofiltration (NF) membranes fabricated by macrocyclic monomers often suffer from inferior ionic rejection due to the commonly formed intermolecular defects among these large molecules. Herein, a patching strategy was employed to fabricate polyarylate-polyamide hybrid NF membrane through interfacial polymerization (IP) by introducing tris(2-aminoethyl)amine (TAEA) with low concentration into Noria solution as the aqueous phase. The polyamide patch could repair the defects of polyarylate film formed by Noria with trimesoyl chloride and endow it with irregularly reticulate morphology. Specially, the Na2SO4 rejection of hybrid NF membrane fabricated with a TAEA doping concentration of 0.03 wt% was improved from 28.1 % to 96.8 %, while it maintained high permeance up to 15.3 L·m−2·h−1·bar−1. In order to compare the intrinsic permeability of fabricated polyarylate-polyamide membrane with other state-of-the-art NF membranes reported recently, the separation layer thickness was normalized. Benefitting from the inner cavity of Noria, its permeability was calculated to be 2.85 L·m−2·h−1·bar−1·μm, which was among the most permeable NF membranes. Additionally, the hybrid NF membrane exhibited excellent anti-compression ability and long-term stability. This patching method as a simple and effective strategy would further promote the application of various macrocyclic molecules in membrane science.