Synthesis of reduced graphene oxide-montmorillonite nanocomposite and its application in hexavalent chromium removal from aqueous solutions

Abstract

A reduced graphene oxide-montmorillonite (GCM) nanocomposite has been synthesized via a simple solvent method. The results showed that reduced graphene oxide and montmorillonite successfully combined together to form nanocomposites. It indicated that the adsorption of Cr(VI) onto GCM nanocomposites was highly pH-dependent with a maximum adsorptive capacity at pH 2.0. The rate of the Cr(VI) adsorption is founded to follow pseudo-second-order kinetics and can also be explained by an intraparticle diffusion model. In addition, the experimental data fit well with the Freundlich isotherm model. The adsorptive capacity of Cr(VI), as determined from the Langmuir isotherm model, is 12.86 mg g⁻¹ at 20 °C. Regeneration studies reveal that Cr(VI)-loaded GCM can be effectively recycled after the treatment with 0.1 mol L⁻¹ NaOH solution, confirming the potential of the as-prepared material for practical application.