Hydrophilic Complexes of the Actinides. I. Carbonates of Trivalent Americium and Europium.

Actinide (III) solubility in WIPP Brine: data summary and recommendations

“…Some of the reported literature stability constants for various reactions are listed in Table 3-2. Lundquist (1982) and Nitsche et al (1989) showed, using two different CO 2 partial pressures, that bicarbonate complexes must be much weaker than reported by Bidolgio (1982); however, his conclusion that the predominant species is Am(CO 3 ) 2 -at 8 ≤ pH ≤9 and -4.4 ≤log 10 [CO 3 2-] ≤-3 is in agreement with the observations of other researchers. 15.2 I = 0 (Felmy et al 1990) 12.8 ±0.25 0.1 NaCl (Giffaut and Vitorage 1993) 11.4 ±0.25 4 M NaCl (Giffaut and Vitorage 1993) 11.44 ±0.12 3 M NaClO 4 (Robouch 1989) Kim et al (1984) measured the solubility of solid Am(OH) 3 (s) at I = 0.1 and 0.3 M NaClO 4 , at pCO 2 = 10 -3.5 atm and interpreted their solubility data assuming the presence of hydroxy, carbonato, and mixed americium hydroxy-carbonato complexes.…”

Rare earth element partitioning between Fe oxyhydroxide precipitates and aqueous NaCl solutions doped with NaHCO3: Determinations of rare earth element complexation constants with carbonate ions.

“…We compare our REE(III)-carbonate complexation constants with the previously reported data obtained by solvent-extraction methods. We cite Eu(III)-carbonate complexation constant data from Lundqvist (1982), Rao and Chatt (1991), Lee and Byrne (1992) and Liu and Byrne (1998) in Table 3. Our results and the literature values were re-calculated at infinite dilution by using the following equations: log log log log log , Activity coefficients for the literature data obtained by using NaClO 4 solutions were calculated according to Millero (1992).…”

“…It is very important to ex-solvent-extraction method of Lundqvist (1982). Solvent-extraction is a classical method for determining stability constants, but the extraction system itself does not correspond to a particular natural reaction system.…”

Proceedings of the workshop on geochemical modeling

“…Two measurements of the distribution of Am(III) between organic and aqueous phases were used here. Lundqvist (1982) measured distribution coefficients in a perchlorate medium (p = 1 H) at pH 4 to 9 (p is ionic strength and M is concentration in molar units). Caceci and Choppin (1983) measured distribution coefficients in a chloride medium (p = 0.7 M) at pH 5.9 and 8.1 as a function of oxalate content and determined the first hydrolysis constant from data for oxalate complexes using competing reactions.…”

“…Lundqvist (1982) measured Am(III) distribution between organic and aqueous phases in perchlorate (yi = 1 M) at pH 4 to 7.5 under 0.1 and 1 atm CO2 pressure. Bidoglio (1982) measured distribution coefficients in perchlorate (p = 0.2 M) at pH 8 to 9 and fixed total carbonate concentrations (1 to 6 mM); equilibrium CO2 pressures were calculated to be 0.0001 to 0.001 atm.…”