Graphene oxide–magnetite nanocomposite as an efficient and magnetically separable adsorbent for methylene blue removal from aqueous solution

We report a facile method to produce a magnetically separable graphene oxide–magnetite nanocomposite (GO–Fe3O4) and its adsorption performance in methylene blue (MB) removal from aqueous solution. The GO–Fe3O4 nanocomposite was synthesized by a solution-phase self-assembly method including the incorporation of monodisperse Fe3O4 nanoparticles (NPs) and GO in a dimethylformamide/chloroform mixture under sonication. The successfully decorating GO sheet with monodisperse Fe3O4 NPs was proved by TEM study. ICP–OES data of the GO–Fe3O4 nanocomposite show that the GO–Fe3O4 nanocomposite consists of 21 wt% Fe3O4 NPs, which is sufficient for its magnetic separation from aqueous solution. The spectroscopic studies reveal that the GO–Fe3O4 nanocomposite is a highly efficient adsorbent for MB removal from aqueous solution, providing an adsorption capacity of 172.6 mg/g, and the equilibrium for MB adsorption is attained in ∼70 min. Moreover, it is a magnetically separable and reusable material for MB removal from water, preserving 87% of its initial efficiency after 5 successive runs.