Facile one-pot synthesis of ultrathin carbon layer encapsulated magnetite nanoparticle and graphene oxide nanocomposite for efficient removal of metal ions

Abstract In the past decades, graphene oxide (GO) exhibited great potential for enhancing the performance of magnetic nanocomposite in the removal of metal ions from aqueous environment. Fabricating GO adsorbents with high stability, excellent adsorption capacity and magnetic responsiveness is a pursuing issue. In this paper, the ultrathin carbon layer encapsulated magnetite nanoparticles and GO nanocomposite (Fe3O4@C-GO) was synthesized by a feasible one-pot hydrothermal method. Scanning electron microscope, transmission electron microscope, Fourier transform infrared, X-ray diffraction, x-ray photoelectron spectrometer, and Raman were conducted to inspect the structure and micromorphology of Fe3O4@C-GO nanocomposite. The results affirmed that the well dispersed Fe3O4 nanoparticles coated by ultrathin carbon layer were successfully combined onto the homogenous flake-like surface of the GO nanosheets containing abundant oxygen functional groups. The surface area and pore volume of the Fe3O4@C-GO nanocomposite were 160 m2/g and 0.283 cm3/g, respectively. The Fe3O4@C-GO nanocomposite was superparamagnetic indicated by VSM. The optimum conditions of the Fe3O4@C-GO nanocomposite as adsorbent for Ag(I), Pb(II), Cr(VI) and Al(III) in aqueous solutions were determined by batch adsorption experiments. The Fe3O4@C-GO nanocomposite exhibited excellent adsorption ability. The maximum adsorption capacities were respectively 162.9 mg/g, 125.8 mg/g, 158.2 mg/g and 173.9 mg/g for Ag(I), Pb(II), Cr(VI) and Al(III), at pH = 6 for Ag(I), Pb(II), and Al(III) as well as pH = 2 for Cr(VI). Adsorption kinetics and isotherms were furtherly investigated. Meanwhile, the adsorption mechanisms of Ag(I), Pb(II), Cr(VI) and Al(III) by Fe3O4@C-GO nanocomposite were detailedly conducted by XPS analysis. Thus, the Fe3O4@C-GO nanocomposite is a promising material for efficient removal of metal ions from aqueous environment.