Efficient antimony removal by self-assembled core-shell nanocomposite of Co3O4@rGO and the analysis of its adsorption mechanism.

Abstract Co3O4@rGO were facilely prepared by template free self-assemble in this study. The morphology of Co3O4@rGO was actiniaria-like core-shell structural nanocomposites. The formation mechanism of Co3O4@rGO core-shell nanocomposite was discussed according to its significant time-dependent morphology evolution course. To evaluate the application potential of Co3O4@rGO, its adsorption performance toward highly toxic antimony ions were studied. The Co3O4@rGO nanocomposite exhibit high anti-interference ability and high adsorption ability. The maximum adsorption capacities towards Sb(III) and Sb(V) are 151.04 and 165.51 mg/g, respectively. River water samples containing antimony violating the limit were used to evaluate the practical application of Co3O4@rGO, and high performance was achieved. The EU and China limits for antimony in drinking water can be met by using mesoporous Co3O4@rGO treating the actual river water samples with original antimony concentration lower than 50 μg/L. Adsorption isotherm, adsorption kinetics, pH and co-existing ions effects were also studied in details. The results indicate that mesoporous Co3O4@rGO is an excellent adsorbent for antimony removal. Mesoporous Co3O4@rGO nanocomposite is a potential candidate for antimony removal from waste water.