A sodium modified reduced graphene oxide–Fe3O4 nanocomposite for efficient lead(ii) adsorption

Abstract

A simple, cost-effective and facile route was employed to synthesize a hydrophobic sodium modified reduced graphene oxide–magnetic iron oxide (SMGI) nanocomposite. The as-synthesized SMGI material was used as an adsorbent material for the removal of Pb(II) from aqueous solutions. The detailed characterization of the SMGI nanocomposite prepared was performed using material characterization techniques. X-Ray Diffraction (XRD) and Fourier transform infrared spectroscopic (FTIR) studies confirm the deposition of crystalline Fe₃O₄ nanoparticles on reduced graphene oxide (rGO). X-ray photoelectron spectroscopic (XPS) analysis shows the presence of 10% sodium cations in the nanocomposite. Transmission Electron Microscopy (TEM) images reveal that the magnetite nanoparticles are homogenously deposited on the 2-dimensional surface of the graphene sheets. The nanocomposite prepared possesses a superparamagnetic property, which was exploited for the easy recovery of the SMGI nanocomposite from water after Pb(II) adsorption. The effects of pH, contact time and concentration on Pb(II) sorption were investigated in detail. The sorption data were fitted using Freundlich and Langmuir models. The pseudo-second-order model was a better fit for Pb(II) adsorption. The maximum adsorption capacity of 1666.66 ± 59 mg g⁻¹ was obtained. The adsorbent also showed more than 75% removal efficiency of Pb(II) after 3 cycles of regeneration.