Reduced graphene oxide as an effective adsorbent for removal of malachite green dye: Plausible adsorption pathways

Efficient removal of malachite green (MG) dye from simulated wastewater is demonstrated using high surface area reduced graphene oxide (rGO). The plausible interaction pathways between MG dye and rGO are deduced from nanostructural features (HRTEM) of rGO and spectroscopic analyses (FTIR and Raman). The high surface area (931m²⋅gm^-1) of rGO, π-π interaction between the aromatic rings of MG dye and graphitic skeleton, and electrostatic interaction of cationic centre of MG dye with π-electron clouds and negatively charged residual oxygen functionalities of rGO collectively facilitate the adsorption of MG dye on the rGO. The rGO displays adsorption capacity as high as 476.2mg⋅g^-1 for MG dye. The thermodynamic parameters calculated from the temperature dependent isotherms suggested that the adsorption was a spontaneous and endothermic process. These results promise the potential of high surface area rGO for efficient removal of cationic dyes for wastewater treatment.