Separation Science and Technology, Vol.34, No.10, 1981-1992, 1999
An assessment of inorganic ion-exchange materials for the removal of strontium from simulated hanford tank wastes
Several inorganic ion-exchange materials were evaluated for the removal of strontium from two simulated Hanford tank wastes (NCAW and 101SY-Cs5) using static batch experiments. Sodium titanium silicate, Na2Ti2O3SiO4. 2H(2)O (NaTS), was the best material in NCAW with a K-d of 2.7 X 10(5) mL/g at a volume-to-mass ratio of 200:1. In the 101SY-Cs5 simulant, strontium extraction was more difficult due to the presence of complexants and consequently K(d)s were greatly reduced. Sodium nonatitanate, NaTi, performed best in the presence of these complexants and gave a K-d of 295 mL/g, though none of the materials performed particularly well. Pellets suitable for column studies were synthesized and the ion exchangers evaluated in column studies. Breakthrough curves correlated well with the Kds Obtained from batch experiments with the sodium titanium silicate performing best in NCAW and a pelletized form of sodium nonatitanate performing best in 101SY-Cs5. Both the sodium titanate and the sodium titanosilicate performed better than IONSIV IE-911, a commercially available ion exchanger, in the NCAW simulant, and consequently could be used for the removal of Sr-90 from highly alkaline tank wastes.