Investigation of uranyl adsorption on mesoporous titanium-based sorbents

Mesoporous titanosilicate sol-gel materials with different silicon to titan ium ratios were prepared by hydrothermal synthesis through the micellar tem plate approach. The prepared samples have been characterized via infrared s pectroscopy, nitrogen sorption, powder X-ray diffraction, and acid-base tit ration. The uptake of uranyl ion (UO22+) by the samples was determined at p H = 5.10. The uranyl loading capacity of the pure mesoporous titania was de termined to be the largest. This capacity is much higher than that of the c orresponding microporous material. The increase of capacity is correlated t o the large surface area induced by the surfactant template synthetic metho d for mesoporous materials, increased concentrations of TiO- surface functi onal ligands, and large pore openings of the mesoporous materials allowing for access to the inner pore surfaces. The adsorption kinetics of our mesop orous sorbents are much faster than those of the corresponding microporous materials. The adsorption equilibria can be reached in less than 15 min.