Performance of biofouling mitigating feed spacer by surface modification using quorum sensing inhibitor

Abstract

Feed spacers are essential components in spiral-wound reverse osmosis (RO) membrane modules and form gaps between membranes while enhancing mass transfer during RO membrane operation. Despite these advantages, long-term operation of feed spacers has considerable influence on biofouling of the membrane filtration process. In this study, biofouling reduction effects were achieved by coating the surfaces of polypropylene (PP) feed spacers with vanillin, which is nontoxic to marine life and highly hydrophilic. A mussel-inspired material, polydopamine (PDA), was also applied for spacer modification to improve the binding forces of both vanillin and polyamide (PA) layer of the membrane. Two coating method was used: PDA was precoated on the surface of PP prior to the vanillin coat (PDA-V spacer) and vanillin co-deposited with polydopamine (PCV spacer). Experimental results showed that the PCV spacer was more appropriate for preventing biofilm formation than the PDA-V spacer, up to 96.7 % and 85.7 % decrease in umber of bacteria for PCV and PDA-V samples, respectively, by delaying microbial community formation. On the other hand, the coated layer eventually peels off when the samples are submerged under water for 100 days or more.