Removal of Pb Ions from Aqueous Solutions Using Melamine Modified Nanographene Oxide

In recent years, various methods have been used to remove heavy metals from aquatic environments; one of which is the adsorption process. Graphene oxide nanoparticles have received much attention due to their high adsorption capacity and high surface area. In this study, melamine-modified nanographene oxide adsorbent was used to remove Pb from aqueous solution. Experiments were performed at pH (3-8), temperature (15-50 °C), Pb concentration (5-200) mg/l, adsorbent (0.01-0.06 g), and contact time (15-150 min). Results showed that the maximum Pb adsorption efficiency by modified nanographene oxide occurred at pH = 6, concentration of 20 mg/l, contact time of 60 min, ambient temperature of 22 °C and adsorbent dosage of 0.01 g. In the study of metal equilibrium isotherms, the Freundlich model was more consistent with the experimental data. Given that the Freundlich model is used to describe heterogeneous adsorbent surfaces, it can be concluded that lead adsorption by graphene oxide nanoparticles has been done in several layers. Modified nanographene oxide with its large surface area, hydrophobicity, high negative charge density, ease of fabrication and high adsorption could be used as an effective adsorbent for metal removal. According to the results of this study, a melamine-modified nanographene oxide adsorbent with a high efficiency of 98.8% can be used to remove lead from aqueous solutions.