Membranes with tunable graphene morphology prepared via Stöber method for high rejection of azo dyes

Abstract

Abstract The study focused on describing the influence of functionalized graphene synthesized by modified Stober method employing vinyltriethoxysilane (VTES) as a precursor. The varying concentration of VTES-G was added in crosslinked polymeric solution for dye rejection. The morphologies of synthesized membranes were envisioned by scanning electron microscope (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM) that displays the formation of silica sphere on graphene thus improving the dispersity of filler in the resultant membranes. The dyes were effectively rejected after VTES-G addition, which were 97.8% (for Congo Red), 99.9% (for Reactive Black 5) and 96.8% (for Reactive Orange 16). The fouling data indicated that modification resulted in improving the antifouling characteristics which caused the decline in the adsorption phenomena of microbes on to the surfaces. The biofouling data showed decrease in the growth of E. coli DH5α cells. Furthermore, the zone inhibition assay depicts that with the addition of VTES-G the inhibition zone value increases for both gram positive and gram negative bacterial strain. As a result, GO functionalization will deliver a promising method to construct graphene based nanofiltration membranes with effectual reinforced permeation and dye selectivity.