Efficient removal of uranium(VI) from aqueous systems by heat-treated carbon microspheres.

In this study, uranium(VI) was successfully removed from aqueous solutions using heat-treated carbon microspheres based on a batch adsorption technique. Influence of the parameters, such as solution pH, contact time, initial uranium(VI) concentration, and temperature on the removal efficiency have been investigated in detail. The results reveal that the maximum adsorption capacity of the heat-treated carbon microspheres toward uranium(VI) is 92.08 mg g(-1), displaying a high efficiency for the removal of uranium(VI) from aqueous solution. The experimental data are analyzed using sorption kinetic models. It is revealed that the process obey the pseudo-second-order kinetic model, the determining step might be chemical sorption. The thermodynamic parameters, such as ΔH°, ΔS°, and ΔG° show that the process is endothermic and spontaneous. This work provides an efficient, fast, and convenient approach for the removal of uranium(VI) from aqueous solutions.