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  • 1 Bhabha Atomic Research Centre Process Engineering and Systems Development Division 400085 Bombay (India)
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Abstract  

Silica-titania gels containing 25, 50 and 75 mol% TiO2 were prepared and the sorption of alkali and alkaline earth metal ions by these materials has been studied. Distribution coefficient values for Cs+ and Sr2+ ions were found to pass through broad maxima as a function of TiO2 content except in the case of Sr under alkaline conditions where there was a continuous increase. Capacity values also increased with TiO2 content and samples containing 50% (for K+ and Cs+), 75% (for Li+ and Na+) and 25%/50% (for Ca2+, Sr2+ and Ba2+) TiO2 exhibited maximum capacities. However, unlike with alkali metals, capacities of a given sorbent for the three alkaline earth ions were almost the same. Large capacities obtained for the latter ions seem to indicate a mineral-forming reaction with 25% and 50% materials. On the other hand, the 25% TiO2 gel seems to sorb Sr at trace level by an ion exchange mechanism. Coupled with its Cs sorption capability, this material may find potential use in large scale decontamination of low level waste solutions.