Promising Enhancement in the Removal of Uranium Ions by Surface-Modified Activated Carbons: Kinetic and Equilibrium Studies

Abstract

Two activated carbons (ac) were prepared by achieving nitric acid oxidation (ox-ac) and iron chloride impregnation (Fe-ac) in order to remove uranium (VI) ions from aqueous solutions. The porosity of the adsorbents was evaluated using the Brunauer-Emmett-Teller (BET) technique, where Infrared (IR) spectroscopy and Boehm’s titration were applied to analyze the surface functional groups of the samples. The scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) techniques were used to identify the structural characteristics of the tested materials. The uranium adsorption of the materials was evaluated in batch experiments. Influencing adsorption factors were investigated. According to this research’s results, it is found that iron-impregnated activated carbon (Fe-ac) presents an excellent adsorption capability for uranium removal compared to acid-treated activated carbon (ox-ac). The uptake capacity is enhanced by 3.32% for Fe-ac, whereas it is only 51.52% for ox-ac. It can be concluded that the uranium adsorption capacity is mainly related to the surface functional groups and the amount of oxygen at the surface of the adsorbents.