Crystalline silicotitanate (CST) ion exchanger is planned to be used to remove cesium (137Cs) from the aqueous phase of Hanford tank wastes in preparation for vitrification at the Waste Treatment and Immobilization Plant (WTP). The average bulk supernate temperatures of the majority double-shell tanks (DSTs) in the Tank Farms currently average around 16 °C during the spring and winter months. Column and batch contact testing with simulants and actual tank waste were conducted at temperatures between 16 °C and 35 ºC to test the impact of operating temperature on ion exchange processes. With a decrease in temperature, CST capacity for Cs increased while the kinetics of the exchange decreased. Based on these results, a determination of temperature impacts on overall mass transfer will allow future modeling of breakthrough performance at a range of process conditions.
