Toxic metal removal from aqueous solution by advanced carbon allotropes: A case study from the Sungun copper mine

This study investigates the sorption efficiencies of graphene oxide (GO) and functionalized multi-walled carbon nanotubes (f-MWCNTs) for the removal of toxic metal ions from acid mine drainage (AMD) sourced from the Sungun copper mine. The objective is to evaluate the potential of these advanced carbon allotropes in treating AMD containing metal ions such as Cu2+, Mn2+, Zn2+, Pb2+, Fe3+, and Cd2+. The preparation of the nanoadsorbents involved the modified Hummers’ method for GO and acid treatment for MWCNTs, followed by characterization using field emission scanning electron microscopy (FE-SEM), Fourier transformed infrared (FTIR) spectroscopy, and BET surface area analysis. A batch method was employed to determine the effects of pH, sorption kinetics, and isotherms. Results indicate that the sorption capacities of MWCNTs improved significantly after oxidation, while those of GO decreased post-reduction, suggesting that chemical interactions between metal ions and the surface functional groups are key to the sorption mechanisms. The adsorption of Cu2+ onto GO was found to fit well with the Langmuir isotherm model, with a high regression constant (R2=0.9981). Overall, the findings highlight GO's promise as an effective material for the removal of toxic metal ions in pollution management.