AdsorptionofCeriumIonsbySiO2/TiO2Aerogels

The adsorption process of Ce(IV) ions instead of Pu(IV) ions by the synthesized SiO2/TiO2 aerogel was investiagted under different adsorption conditions. The porous SiO2/TiO2 aerogel with the great specific surface area of 1000.499 m2/g and the narrow pore size distribution was prepared via a sol-gel process and subsequent phase separation and ambient pressure drying. The measured adsorption process follows the pseudo-second-order kinetic equation. The detailed information on the geometry of the cerium adsorption sites were reported. The cerium ions were absorbed primarily due to the electrostatic forces and ion exchange reactions.The adsorption equilibrium time is 64 h at the optimal SiO2/TiO2 aerogel dosage of 6 g/L. 55.58% of Ce(IV) in the SiO2/TiO2 aerogel as an adsorbent is obtained at < 2 h, and the maximum adsorption capacity is 233.04 mg/g. In addition, according to the thermodynamic analysis, the adsorption process is endothermic and accelerating. The chemically-modified SiO2/TiO2 gel with sulfonic acid has a extremely high adsorption to Ce(IV) ions, and can even extract the trace amounts. The constants of SiO2/TiO2 aerogel as an adsorbent can be applied to predict the optimum reaction parameters to adsorb the nuclide in liquid waste.