PNNL

Abstract

Crystalline silicotitanate (CST) ion exchange media is currently utilized in the Tank Side Cesium Removal (TSCR) system on the Hanford site to remove Cs-137 from tank waste supernate. Ongoing batch contact experiments with CST have been done to tease out the impact of group II metals, anions, potassium, and temperature on Cs removal to better understand bounding conditions for operations as well as aid in development of a wholesome isotherm model to predict Cs behavior in the tank waste. This paper discusses the impact of Na concentration on Cs exchange and provides insight to the challenges associated with activity coefficient estimations for modeling Cs distribution in tank waste matrices.