Proficiency of Few-Layered Graphene Oxide Nanosheets as Promising Sorbents for Dye Pollution Management

Abstract

Graphene is an evolving class of carbon nanomaterials whose exceptional adsorption features toward organic compounds have not been well understood. In the current research, a modified Hummers’ technique was adopted to synthesize the graphene oxide nanosheets (GONS) from graphite to investigate its adsorption efficiency to remove methylene blue dye (MB) from aqueous solutions. Response surface methodology (RSM) was applied to optimize the removal parameters, namely, pH, contact time, and adsorbent dosage. The as-synthesized GONS displayed 98.8% removal efficiency, the kinetics data were described properly by the pseudosecond-order model, and the maximum adsorptive uptake suggested by the Langmuir model was 270 mg g1. Unlike most previous works, which reported that the MB adsorption onto graphene oxide occurs in monolayers, in this study, the equilibrium data were best fitted to the Temkin model. It was proposed that the π-π electron donor-acceptor mechanism and the electrostatic interactions play an important role in the adsorption process. The results suggest that the GONS is a good candidate to be synthesized on a large scale for potential application in dye-bearing wastewater treatment.