High performance solvent resistant nanofiltration membranes are fabricated via interfacial polymerization between m-phenylenediamine and 1,2,4,5-benzenetetra acylchloride on hydrolyzed polyacrylonitrile supports followed by chemical imidization.

Coordination interaction between transition metal Cu 2+ ions and polyelectrolyte (PE) ligand is studied to prepare (PEI/PSS(Cu)1/2)n layer-by-layer (LBL) self-assembly (SA) nanofiltration (NF) membranes with unique antibacterial property. The coordination interaction mechanism has been clearly illustrated by X-ray photoelectron spectroscopy (XPS) analysis of the chemical composition of the active skin layer, the result reveals that about one third of the Cu 2+ ions is involved in the interaction. The prepared (PEI/PSS(Cu)1/2)5 LBL membrane owns relative smooth surface morphology and good separation performance, with permeation flux of 65 L m −2 h −1 and rejection of about 84% for SO4 2− at 1.0 MPa. It has excellent antibacterial rate up to 94.2%. The performance of the LBL membranes could be improved, after cross-linking by glutaraldehyde (GA). This kind of LBL NF membrane shows potential application in the separation of monovalent and divalent anions.The influence of bilayer number on the performance of LBL membranes was carried out with five different bilayers (1, 2, 3, 4, 5) prepared using anionic PE solution of 0.4 M CuCl 2 and 0.4% PSS, and cationic PE solution of 0.5 M NaCl and 0.3% PEI. CharacterizationFig.3 The effect of number of bilayers (n=1-5) on rejection (a) and flux (b) of the prepared LBL (PEI/PSS(Cu) 1/2 ) n membranes with different substrates and deposition sequences Fig.7 SEM images of H-PAN substrate and the prepared LBL (PEI/PSS(Cu) 1/2 ) 5 membrane (surface: substrate (a) and (PEI/PSS(Cu) 1/2 ) 5 (b); cross-section: substrate (c) and (PEI/PSS(Cu) 1/2 ) 5 (d)) Fig.8 AFM images of H-PAN substrate (2D images (a) (c) and 3D image (e)) and the prepared LBL (PEI/PSS(Cu) 1/2 ) 5 membrane (2D images (b) (d) and 3D image (f))