Determination of the stability constants of Pu(VI) carbonate complexes by capillary electrophoresis coupled with inductively coupled plasma mass spectrometer

Abstract

Abstract New determination of the stability constants related to the Pu(VI)/carbonate chemical system has been obtained by coupling capillary electrophoresis and ICP-MS at the ionic strength of 0.202 m in NaClO4 and for a temperature of 25°C. The following values have been obtained: log 10 β PuO 2 CO 3 = 8.12 ± 0.02 , ${\log _{10}}{\beta _{{\rm{Pu}}{{\rm{O}}_2}{\rm{C}}{{\rm{O}}_3}}} = 8.12 \pm 0.02,$ log 10 β PuO 2 ( CO 3 ) 2 2 − = 13.96 ± 0.04 , ${\log _{10}}{\beta _{{\rm{Pu}}{{\rm{O}}_2}({\rm{C}}{{\rm{O}}_3})_2^{2 - }}} = 13.96 \pm 0.04,$ and log 10 β PuO 2 ( CO 3 ) 3 4 − = 18.10 ± 0.03. ${\log _{10}}{\beta _{{\rm{Pu}}{{\rm{O}}_2}({\rm{C}}{{\rm{O}}_3})_3^{4 - }}} = 18.10 \pm 0.03.$ Based on the values selected by AEN/OECD, the interaction coefficients have been re-evaluated as follows: ε PuO 2 CO 3 = 0.02 ± 0.21 , ${\varepsilon _{{\rm{Pu}}{{\rm{O}}_2}{\rm{C}}{{\rm{O}}_3}}} = 0.02 \pm 0.21,$ ε PuO 2 ( CO 3 ) 2 2 − , Na + = 0.12 ± 0.08 , ${\varepsilon _{{\rm{Pu}}{{\rm{O}}_2}({\rm{C}}{{\rm{O}}_3})_2^{2 - },{\rm{N}}{{\rm{a}}^ + }}} = 0.12 \pm 0.08,$ ε PuO 2 ( CO 3 ) 3 4 − , Na + = 0.14 ± 0.18  kg ⋅ mol − 1 . ${\varepsilon _{{\rm{Pu}}{{\rm{O}}_2}({\rm{C}}{{\rm{O}}_3})_3^{4 - },{\rm{N}}{{\rm{a}}^ + }}} = 0.14 \pm 0.18{\rm{ kg}} \cdot {\rm{mo}}{{\rm{l}}^{ - 1}}.$