Plasma treatment of polypropylene and polysulfone supports for thin film composite reverse osmosis membrane

Low temperature plasma treatment of membrane supports was carried out to investigate the performance enhancement of thin film composite (TFC) reverse osmosis membrane. Commercial polypropylene (PP) microfiltration membrane (Celgard 2400) and polysulfone (PSf) ultrafiltration membrane prepared by conventional phase inversion method were plasma treated before interfacial polymerization. Hydrophilic monomers such as acrylic acid, acrylonitrile, allylamine, ethylenediamine and n-propylamine were used to hydrophilize the support membrane. Hydrophilic plasma treatment of PSf support showed slightly enhanced flux and rejection of TFC membrane when compared to the values of conventional TFC membranes. Plasma treatment remarkably enhanced the performance of membrane with PP support. It enabled PP support to be used for TFC membrane, which was not possible so far due to PP's hydrophobicity. Performance enhancement by plasma treatment of the supports was interpreted in terms of surface chemical composition and contact angle. Plasma treatment of supports enhanced not only the adhesion properties between active layer and support but also the chlorine resistance of the composite membrane.