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It was found that rGO were exfoliated and decorated homogeneously with CNF nanoparticles having diameters of 20 nm. The saturated magnetization (Ms) value was estimated to be 60 emu/g, remanences (Mr) and coercive forces (Hc) near to zero, indicating that obtained material is superparamagnetic. The pH effect, contact time and adsorption isotherms were examined in batch experiments. The adsorption isotherm agreed well with the Langmuir model, having a maximum adsorption capacity of 256 mg/g, at pH = 6, T = 298 K. | Journal of Science and Technology 54 (5A) (2016) 9-18 ADSORPTION OF URANIUM FROM AQUEOUS SOLUTION BY Cu0.5Ni0.5Fe2O4 – REDUCED GRAPHENE OXIDE NANOCOMPOSITES Tran Quang Dat*, Nguyen Van Toan, Pham Van Thin, Do Quoc Hung Le Quy Don Technical University, 236 Hoang Quoc Viet Street, Hanoi, Viet Nam. * Email: dattqmta@gmail.com Received: 15 July 2016; Accepted for publication: 2 December 2016 ABSTRACT Cu0.5Ni0.5Fe2O4 – reduced graphene oxide composites (CNF-rGO) as an efficient adsorbent for the adsorption of uranium (VI) have been synthesized by a two-steps methods. The structures and the physicochemical properties of adsorbents are characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy (RAMAN) and Vibrating sample magnetometer (VSM) measurement. It was found that rGO were exfoliated and decorated homogeneously with CNF nanoparticles having diameters of 20 nm. The saturated magnetization (Ms) value was estimated to be 60 emu/g, remanences (Mr) and coercive forces (Hc) near to zero, indicating that obtained material is superparamagnetic. The pH effect, contact time and adsorption isotherms were examined in batch experiments. The adsorption isotherm agreed well with the Langmuir model, having a maximum adsorption capacity of 256 mg/g, at pH = 6, T = 298 K. Keywords: reduced graphene oxide, Cu0.5Ni0.5Fe2O4, nanocomposites, uranium, adsorption. 1. INTRODUCTION Hexavalent actinides constitute a significant proportion of the radioactive species distributed in nuclear waste, and are generated in the post-processing of spent fuels every year. Uranium is a toxic heavy metal arising from the nuclear industry as well as from anthropogenic activities. The hexavalent uranyl ion (UO22+) is found to be the most stable form in vivo, and its compounds can cause irreversible renal injury and potential carcinogens [1]. Removal of U(VI) from aqueous solutions is very important. There are various methods to treat U(VI) from aqueous solutions, .