Actinide oxalate complexes formation as a function of temperature by capillary electrophoresis coupled with inductively coupled plasma mass spectrometry

Abstract

confirmed the formation of the 1 : 1, 1 : 2 and 1 : 3 complexes for U(VI) and Am(III); the formation of the 1 : 1 and 1 : 2 complexes for Np(V) and the formation of only 1 complex for Pu(V). For each complex, the thermodynamic parameters (the Gibbs energy Δ r ( ), the molar entropy change Δ r ( ) and the molar enthalpy change Δ r ( 0 )) were fitted to the experimental data. The effect of the ionic medium was treated using the specific ion interaction theory and the thermodynamic parameters at zero ionic strength were compared to previously published data.

Affinity capillary electrophoresis in studying the complex formation equilibria of radionuclides in aqueous solutions

“…The obtained thermodynamic parameter values are consistent with literature data . The ACE has also been fruitfully used for study the temperature influence on stability constants of selenate with a number of metal ions (UO 2 2+ , Ca(II), Mg(II), Co(II), Ni(II), Cu(II) and Cd(II)) and of oxalate with U(VI), Np(V), Pu(V) and Am(III) . Thus, ACE can successfully compete with the traditionally used calorimetric method for determination of thermodynamic parameters.…”

“…The ACE has recently been used to determine the stability constants of uranyl citrate complex and a number of actinide oxalate complexes . The more detailed information on stability constant determination of metal and actinide ions with diverse ligands obtained by ACE can be also found in recent reviews .…”

Determination of the Stability Constants of the Acetate Complexes of the Actinides Am(III), Th(IV), Np(V), and U(VI) Using Capillary Electrophoresis-Inductively Coupled Plasma Mass Spectrometry

“…Complex binding constants have been determined for actinides with CE-ICP-MS for various ligands by Aupiais et al such as sulfate and chloride, carbonate, nitrate, oxalate, − and diethylenetriaminepentaacetic acid. , Furthermore, affinity CE has been used for the investigation of the interaction of Np­(V) and U­(VI) with acetate, but no coupling with ICP-MS was performed. Therefore, for the actinide–acetate system there are no studies described using a coupling between CE and ICP-MS, and, as mentioned above, all the available literature for this system provides data for actinide concentrations orders of magnitude higher than those used in this work.…”

A spectrophotometric study of the impact of pH and metal-to-ligand ratio on the speciation of the Pu(vi)-oxalate system

“…However, additional spectrophotometric, potentiometric, calorimetric, and capillary electrophoresis ICP-MS studies of the U(VI)-oxalate system were published after the NEA-TDB review. [50][51][52][53] These studies provide a smaller range of values for the absolute formation constant of the UO 2 (C 2 O 4 )(aq) complex (i.e., log b1 = 6.96-7.71) and the absolute formation constant for the [UO 2 (C 2 O 4 ) 2 ] 2À complex (i.e., log b1 = 11.45-12.07). The most notable observation of these more recent studies is the comparison of stability constants across the actinide series conducted by Brunel et al, 53 who discuss stability constants obtained through capillary electrophoresis techniques at 25 1C and extrapolated to zero ionic strength by SIT for U(VI), Np(V), Pu(V), and Am(III).…”