Thin-Film Composite Polyamide Membranes Functionalized with Biocidal Graphene Oxide Nanosheets

Fouling of membranes by microorganisms is a major limiting factor in membrane separation processes. Novel strategies are therefore required to decrease the extent of bacterial growth on membranes. In this study, we confer strong antimicrobial properties to thin-film composite polyamide membranes by a simple graphene oxide surface functionalization. Using amide coupling between carboxyl groups of graphene oxide and carboxyl groups of the polyamide active layer, graphene oxide is irreversibly bound to the membrane. Surface binding of graphene oxide is demonstrated by scanning electron microscopy and Raman spectroscopy. Direct contact of bacteria with functionalized graphene oxide on the membrane surface results in 65% bacterial inactivation after 1 h of contact time. This bactericidal effect is imparted to the membrane without any detrimental effect to the intrinsic membrane transport properties. Our results suggest that functionalization of thin-film composite membranes with graphene oxide nanosheets is a promising approach for the development of novel antimicrobial membranes.