The adsorption of Cr(VI) from an aqueous medium using magnetically functionalized cobalt nanoparticles-reduced graphene oxide (Co-rGO) was studied. Co-rGO was synthesized using the co-precipitation method. Graphene oxide and cobalt acetylacetonate were reduced together in water using sodium borohydride as a reducing agent. CorGO was used as the adsorbent material for the removal of dichromate ions in water. The prepared Co-rGO was characterized using powder X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) surface area analysis. Selected area electron diffraction was used to determine that the cobalt nanoparticles were on the surface of the reduced graphene oxide. The effect of the mass of the adsorbent material (Co-rGO), the concentration and pH of the Cr(VI) containing solution and the time of contact between the adsorbent and the Cr(VI) on the adsorption efficiency were investigated. It was found that the optimum adsorbent mass for the efficient removal of Cr(VI) from a fixed concentration of Cr(VI) of 100mg L?1 was 0.015 g, the optimum pH of the solution was 8, and the optimum contact time was 90 minutes. The experimental data obtained were fitted to the Langmuir, Freundlich, and Lui isotherms to obtain the characteristic parameters of each model. The experimental data fitted well to the Freundlich isotherm. The thermodynamic data was used to evaluate the nature of the adsorption. It was determined that the sorption process was physisorption. The kinetics of the adsorption process followed pseudo-second-order kinetic model.

Magnetic Properties Adsorption Magnetic Nanoparticles Cr(VI) Cobalt Nanoparticles

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