A surface-modified EDTA-reduced graphene oxide membrane for nanofiltration and anti-biofouling prepared by plasma post-treatment

Abstract

Surface-modified EDTA-reduced graphene oxide (EDTA-rGO) membranes with high rejection rates, for monovalent ions, in particular, were fabricated from graphene oxide (GO) for nanofiltration. The EDTA-rGO membrane surface was treated with oxygen plasma to enhance its water permeability (P-EDTA-rGO). The resulting P-EDTA-rGO membrane demonstrated rejection rates of more than 80% for NaCl and water permeabilities of approximately 150 LMH bar⁻¹, which are approximately 15 times higher than those before the treatment, without sacrificing the ion rejection performance for small ions. The high rejection rates and permeabilities of the P-EDTA-rGO membrane are presumed to originate from the small interlayer spacing (remains comparably small even in a wetted state; 5.7 Å) resulting from EDTA functionalization and the enhanced hydrophilicity due to plasma treatment. In addition, the membrane impeded bacterial adhesion.