Synthesis of graphene/silica composites and its removal efficiency of methylene blue dye from water

Abstract

Water supply remains constant; however, industrial wastewater has been raised. Due to the high demand for clean water, there is a continued need for water treatment. Here, graphene nanoplatelets modified with silicon dioxide nanoparticles were synthesized and characterized. Structural, surface morphology and physichemical characteristics of GNP-SiO2 were characterized by FTIR, XRD, and SEM. The nanocomposite was assessed for methylene blue (MB) adsorption from wastewater. To study the impact of the adsorption parameters, the factorial design with multivariate method central design, analysis of variance, response surface 3D graph, Pareto Chart, and Normal probability plot was used. The experimental equilibrium data fit with the Langmuir isotherm model. Removal capacity (qm) was 495 mg g−1 for GNP-SiO2 nanocomposite with the formation of monolayer coverage and specific homogenous sites on GNP-SiO2 nanocomposite. The kinetic mechanism suggested that the PSO model fits kinetic MB removal mechanisms over the GNP-SiO2 nanocomposite and progressed profoundly via chemisorption. The MB cationic dye removal by GNP-SiO2 nanocomposite was by electrostatic attraction, hydrogen bond, and π–π interactions as well as the surface adsorption. The results revealed that prepared GNP-SiO2 nanocomposite was effective for MB adsorption from aquatic solution.