Reduced Temperature Cesium Removal from AP-107 Using Crystalline Silicotitanate

Effect of Na Concentration on Cs Distribution with Crystalline Silicotitanate in Tank Waste Simulants

“…The Harvie formalism was applied in the calculation of the activity coefficients, and the results are shown in Table 6. Now, we can estimate the K d × [Na] from the activity coefficients (with an assumed constant) according to (10) and (11) So that (12) Results of the K d × [Na] fits as predicted from the Bromley and HSC calculations of activity coefficients compared to the experimental data at each Na concentration is shown in Figure 5. The HSC fit appears to follow more of the curvature observed for experimental results, whereas the Bromley fit is more linear.…”

“…The simulants were prepared to achieve a Na concentration of 8.0 M. The concentrations of the additional anions in Simulant II were derived from an approximation of the anions in Hanford tank waste, adjusted to ∼8.0 M Na, as shown for AP-107 in Table . It is important to note that analytical results from AP-107 tank waste at 6.2 M Na did contain 0.1 M K + (adjusted to 0.13 M K+ at 8.0 M Na), which was omitted from simulant preparation …”

“… a Data taken from Westesen et al b Estimated from IC results at [Na] = 5.9 M. c From TIC measurement. …”

“…In addition to the two simulants, Cs-decontaminated AP-107 tank waste was used as a matrix to test the impact of Na concentration on Cs removal from actual waste. AP-107 tank waste was obtained following ion exchange processing (described extensively elsewhere), where 8.0 L of AP-107 supernate was processed through two 10.0 mL CST ion exchange columns sequentially positioned in a lead-lag format at 16 °C . The Na concentration in the feed solution was measured to be 6.2 M Na with 162 μg/mL 137 Cs.…”

“…AP-107 tank waste was obtained following ion exchange processing (described extensively elsewhere), where 8.0 L of AP-107 supernate was processed through two 10.0 mL CST ion exchange columns sequentially positioned in a lead-lag format at 16 °C. 11 The Na concentration in the feed solution was measured to be 6.2 M Na with 162 μg/mL 137 Cs. The Csdecontaminated AP-107 effluent was used to prepared solutions of variable Na concentration.…”