Modifying the surface of active polyamide layer in thin-film composite tubular membranes with polyethylene glycol for improved separation and antifouling

Background: Membrane fouling can deteriorate the membrane performance for the long term. Surface modification of the membrane using hydrophilic moieties improves the antifouling property of the membrane. In this study, thin-film composite (TFC) polyamide tubular membrane was modified using glutaraldehyde (GA) and polyethylene glycol (PEG). Methods: Polyamide layer was formed through interfacial polymerization of piperazine (PIP) with trimesoyl chloride (TMC). Before modification using PEG on the surface of the TFC membrane, the TFC membrane was post-treated using GA. The aldehyde group of the GA reacted with free amines on the polyamide surface, producing enamine. PEG modified the GA-TFC membrane through the reaction of excess aldehyde group of the GA on the membrane surface. Findings: PEG-GA-TFC membrane shows a better hydrophilicity and membrane surface charge than pristine and GA-TFC membrane. Consequently, during nanofiltration test, it delivered the highest membrane performance and antifouling property (tested using 100 ppm BSA solution). Furthermore, the modified membrane exhibited good stability in a wide range of pressure and salt concentration. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.