Laminar reduced graphene oxide membrane modified with silver nanoparticle-polydopamine for water/ion separation and biofouling resistance enhancement

Abstract

Laminar graphene oxide (GO) membranes with excellent water permeability have demonstrated great potential in the field of membrane-based water purification. However, low ion rejection and controversy over their biofouling propensity are hurdles GO membranes face in realizing commercial applications. This study shows that silver nanoparticle (nAg)@polydopamine (pDA) deposition on chemically reduced GO (rGO) laminates can simultaneously enhance both biofouling resistance and ion rejection. In pressurized filtration tests, the salt rejection of nAg@pDA-rGO membranes outperformed that of GO membranes despite its lowered water permeability. In osmotic filtration tests, nAg@pDA-rGO membranes achieved an increased water flux of 28.9LMH and reduced reverse solute flux of 0.21mol/m2·h, compared to GO membranes. Moreover, extremely low cell attachment and viability were seen on the nAg@pDA-rGO membrane, confirming the excellent antibiofouling ability of nAg-pDA-rGO membranes.