Experimental Determination of Water Activity for Binary Aqueous Cerium(III) Ionic Solutions:  Application to an Assessment of the Predictive Capability of the Binding Mean Spherical Approximation Model

Abstract

This work is aimed at a description of the thermodynamic properties of actinide salt solutions at high concentration. The predictive capability of the binding mean spherical approximation (BIMSA) theory to describe the thermodynamic properties of electrolytes is assessed in the case of aqueous solutions of lanthanide(III) nitrate and chloride salts. Osmotic coefficients of cerium(III) nitrate and chloride were calculated from other lanthanide(III) salts properties. In parallel, concentrated binary solutions of cerium nitrate were prepared in order to measure experimentally its water activity and density as a function of concentration, at 25 degrees C. Water activities of several binary solutions of cerium chloride were also measured to check existing data on this salt. Then, the properties of cerium chloride and cerium nitrate solutions were compared within the BIMSA model. Osmotic coefficient values for promethium nitrate and promethium chloride given by this theory are proposed. Finally, water activity measurements were made to examine the fact that the ternary system Ce(NO3)3/HNO3/H2O and the quaternary system Ce(NO3)3/HNO3/N2H5NO3/H2O may be regarded as "simple solutions" (in the sense of Zdanovskii and Mikulin).

Influence of Imidazolium Ionic Liquids on the Interactions of Human Hemoglobin with DyCl3, ErCl3, and YbCl3 in Aqueous Citric Acid at T = (298.15, 303.15, and 308.15) K and 0.1 MPa

“…The densities of LnCl 3 with WC, WCH, WCHL 2 , WCHL 4 , and WCHL 6 at 298.15, 303.15, and 308.15 K are in the order: YbCl 3 > ErCl 3 > DyCl 3 . This trend indicates that Yb 3+ with highest charge density (Dy 3+ = 5.27 nC·m –1 , Er 3+ = 5.40 nC·m –1 , and Yb 3+ = 5.53 nC·m –1 ) develops the strongest ion–ion and ion–hydrophilic interaction (IHI) with the −COO – , −OH, −COOH, and >CO groups present in WC, WCH, and WCHILs and also with the bulk water molecules, while Dy 3+ with the lowest charge density develops the weakest IHI. As the charge density of Ln 3+ increases, the hydrophilic groups (−COO – , −OH, and >CO) are able to approach the Ln 3+ ions more closely with increasing propensity of the hydrophobic domains to aggregate.…”

Modeling the Osmotic and Activity Coefficients of Lanthanide Nitrate Aqueous Solutions at 298.15 K from Low Molalities to Supersaturation

“…In some cases (La, Tb, and Yb in Figures S1-1A, S1-8A, and S1-13A, respectively, with the prefix S1 denoting figures in Supporting Information 1), their data cover the molality range below 0.1 mol kg −1 and can thus be assessed against the data obtained from freezing point or conductance techniques. For comparison, we have recalculated the osmotic coefficients from the measured values of a w provided by Chatterjee et al 13 and Ruas et al 28 using eq 2. In some cases, we also calculated the osmotic coefficients of the lanthanide nitrate solutions from the LLNL/Ames data using eq 14.…”

“…In the case of lanthanide−nitrate aqueous solutions, there is experimental evidence of ion pairs 25−27 and the modeling of these solution properties suggests that their role is far from negligible. 28 However, to the best of the authors' knowledge, there appears to be no experimental data on lanthanide−nitrate ion pairs in the literature that would be sufficiently comprehensive to parametrize the classical Pitzer equations. Consequently, the option adopted in the present work relies on the assumption of full dissociation and on the use of the β (2) parameter.…”

Thermodynamic modeling of neodymium and cerium oxalates reactive precipitation in concentrated nitric acid media

“…For cerium, we used the data reported by Ruas et al (2005) (in pure water) and Torres-Arenas et al (2010) (in HNO 3 ). Due to the small amount of results available for Ce(NO 3 ) 3 , and in order to model the latter with sufficient precision, complementary experimental data were measured for HNO 3 concentrations ranging from 0 (so to obtain data of the binary mixture Ce(NO 3 ) 3 -H 2 O, which could be compared to those existing in literature (Ruas et al, 2005) to 1 m, and Ce(NO 3 ) 3 concentrations ranging from 0.1 to 3 m. The obtained water activity results are reported in Table 2.…”