Effective adsorption of uranium(VI) from aqueous solution using ethylene-bridged mesoporous silica functionalized with ureido groups

Ureido-functionalized ethylene-bridged mesoporous silica (UE-MS) was synthesized by co-condensation method for uranium(VI) uptake. The adsorbents were characterized by SEM, EDS, FTIR, BET and TGA. Through batch experiments, the effects of main factors on U(VI) sorption were investigated. The results indicated this adsorption was very fast with an equilibrium time of 30 min and negligibly affected by coexisting cations. At the optimum pH of 7, removal efficiency can exceed 99% with only 0.6 g/L of UE-MS dose. Furthermore, the adsorption process by UE-MS followed the quasi-second-order model and Freundlich model, and this process was spontaneous and endothermic.