Graphene and activated graphene as adsorbents for removal of heavy metals from water resources

Abstract

In the current study, graphene, synthesized in the laboratory for nanomaterials of the Faculty of Technology and Metallurgy in Skopje, marked as G-ASP2, was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and thermogravimetric analysis (TGA). The acid activation of the G-ASP2 was performed using concentrated H2SO4 and HNO3. The aim of this work was to investigate the adsorption ability of graphene, G-ASP2, and its activated form AG-ASP2, in the removal of Ni(II), Pb(II), and Fe(II) ions from aqueous solutions. The influence of the adsorption time on the efficiency of heavy metal ion removal was studied, and thus the analysis of the process kinetics was carried out. The study found that for all examined systems, the adsorption process followed the pseudo second-order kinetic model. The comparison of the removal percentage of metal ions in the single and multimetal systems was also performed. Therefore, graphene and activated graphene are promising adsorbents for Ni(II), Pb(II), and Fe(II) removal from polluted water.