Surface photochemical graft polymerization of acrylic acid onto polyamide thin film composite membranes

Surface modification is an effective approach to enhance the properties of polymeric membranes. In this work, the UV-photo-induced graft polymerization of acrylic acid (AA) onto the surfaces of polyamide thin film composite (TFC-PA) membranes was carried out using an immersion method performed under ambient conditions. The experimental results indicate that the membrane surface becomes more hydrophilic because of the appearance of new carboxylic groups on the surface after the modification. This reduces the water contact angle and increases the water permeability compared with the unmodified membrane. The membrane surface is relatively compact and smooth due to the formation of the polymeric AA-grafted layer. The separation performance of the modified membrane is improved with enhancements of the permeate flux and the retention of humic acid from aqueous feed solutions compared with those of the unmodified membrane. The fouling resistance of the membrane is also improved because of the higher maintained flux ratios and the lower irreversible fouling factors for the removal of various organic compounds from feed solutions. (C) 2016 Wiley Periodicals, Inc.