Preparation and characterization of nanofiltration composite membranes using polyacrylonitrile (PAN). II. Preparation and characterization of polyamide composite membranes

Polyamide (PA) composite membranes in which PA active layers were interconnected with support layers via the formation of ionic bonds were prepared by the interfacial polymerization of piperazine (PIP) with trimesoyl chloride (TMC) on the surfaces of microporous polyacrylonitrile (PAN) supports containing carboxylic acid groups. Formation of the ionic bonds through an acid-base reaction between -NH group of PIP and -COOH of the support was studied using FTIR-ATR spectroscopy. Variation of the surface morphologies of the composite membranes that was induced by the presence of the ionic bonds was observed with a FESEM and an AFM. Permeation tests with various feed solutions such as PEG 600, Na2SO4, MgSO4, MgCl2, and NaCl solutions were carried out to see how the characteristics of the PAN supports affected on the flux and rejection of the corresponding PA composite membranes. Chemical stabilities of the composite membranes with the ionic bonds were studied and compared with that of a conventional PA composite membrane, using alcohol solutions. (C) 2001 John Wiley & Sons, Inc.