Synthesis of RGO/γ-Fe₂O₃ nanocomposite for the removal of heavy metals from aqueous solutions

Abstract Reduced graphene oxide/maghemite (RGO/γ-Fe2O3) material was successfully synthesized by combining the modified Hummers method with co-precipitation (RGO 10 wt.%). γ-Fe2O3 nanoparticles with a particle size of ∼14.8 nm were distributed on the surface of RGO sheets. Results of Brunauer–Emmett–Teller analysis showed that RGO/γ-Fe2O3 had a mesoporous structure and a narrow capillary size distribution curve at about 13 nm. The specific surface area of the RGO/γ-Fe2O3 was 168 m2·g−1. The RGO/γ-Fe2O3 nanocomposite was used to adsorb arsenic As(V) and a mixture of heavy metals (As(V), Cr(VI), Pb(II), and Fe(III)) in water. The maximum adsorption efficiency of As(V) reached 98.9% after 45 min with an adsorption capacity of 5.93 mg·g−1, higher than the simultaneous adsorption of the four metal ions. Competitive adsorption decreased in the order As(V), Cr(VI), Pb(II), and Fe(III). Therefore, RGO/γ-Fe2O3 could be used as an effective adsorbent to remove heavy metals from aqueous solutions.