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

Reduced graphene oxide/maghemite (RGO/gamma-Fe2O3) material was successfully synthesized by combining the modified Hummers method with co-precipitation (RGO 10 wt.%). gamma-Fe2O3 nanoparticles with a particle size of & SIM;14.8 nm were distributed on the surface of RGO sheets. Results of Brunauer-Emmett-Teller analysis showed that RGO/gamma-Fe2O3 had a mesoporous structure and a narrow capillary size distribution curve at about 13 nm. The specific surface area of the RGO/gamma-Fe2O3 was 168 m(2)& BULL;g(-1). The RGO/gamma-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 & BULL;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/gamma-Fe2O3 could be used as an effective adsorbent to remove heavy metals from aqueous solutions.