A literature survey of mineral-specific sorption data on radionuclides with relevance to the disposal of radioactive waste

Delakowitz, Bernd; Meinrath, G.; Spiegel, W.

doi:10.1007/bf02165243

Cited by 6 publications

(3 citation statements)

References 13 publications

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“…Recent work however indicates, that essential gaps and uncertainties exist in current knowledge of thermodynamic data relevant in geochemical modelling of uranium. Lacking or questionable thermodynamic data concerns especially mineral phases [9,11,14], solution species [7,20,36,47] and retention/sorption data [6,55] of uranium(VI). The reliability of thermodynamic data of U(VI) hydrolysis must be seen sceptical, too on basis of model-free chemometric and statistical analysis.…”

Section: Discussionmentioning

confidence: 99%

Chemometric and Statistical Analysis of Uranium(VI) Hydrolysis at Elevated U(VI) Concentrations

Meinrath

1997

Radiochimica Acta

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26 UV-Vis spectra of U(VI) samples in the pH range 2.4 to 4.8 and U(VI) concentration range 6 · 10"' M to 2 · 10" 4 M in 0.1 M aqueous Perchlorate solutions are analyzed simultaneously by model free techniques, e.g. factor analysis, target rotation and non-parametric statistics. Within the investigated range of conditions, three factors only are found to be significantly contributing. UOHaq), (U0 2 ) 2 (0H)r and (U0 2 ),(0H)í are found as the relevant species. A single component spectrum of the (U0 2 )I(0H)Î species is derived with a molar absorption of ε, 5 = 474±7 1 mor' cm"' at the absorption maximum at 429.0 nm of the low-energy electronic transition of uranium(VI). The complete set of 26 spectra is simultaneously interpreted by Target Factor Analysis. The evaluated formation constants are lg K22 = -6.14,±0.08« of (U0 2 ) 2 (0H)r from 21 observations and lg K', 5 = -17.14 2 ±0.13" of (U0 2 ) 3 (0H)J from 14 observations. Owing to the importance of pH determination in evaluating thermodynamic data of hydrolysis species, a rigorous statistical approach to the evaluation of pH by a multistandard calibration procedure is chosen.

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Section: Discussionmentioning

confidence: 99%

Chemometric and Statistical Analysis of Uranium(VI) Hydrolysis at Elevated U(VI) Concentrations

Meinrath

1997

Radiochimica Acta

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“…This example shows that a value of a quantity of interest, here a K D value, may become easily inaccessible due to the limited resolution of the experimental method. The considerable variance in K D values in combination with the very limited applicability have been recognised as a major problem in geochemical modelling [23].…”

Section: ϫ10mentioning

confidence: 99%

Sorption of Iron on Surfaces: Modelling, Data Evaluation, and Measurement Uncertainty

Meinrath

Merkel

Ödegaard-Jensen

et al. 2004

Acta hydrochim. hydrobiol.

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Assessment of the likely outcome of engineered invention strategies in acid mine drainage often involves complex geochemical modelling activities. Geochemical modelling is based on chemical thermodynamic data. In addition sorption models, kinetical reaction rates and transport tools are included into the modelling codes because the interactions between solution components and surfaces, reaction time and transport are considered important features characterising the site‐specific situation. In the determination of both thermodynamic data and sorption coefficients, speciation calculations play an important role. By applying the probabilistic speciation code Ljungskile to some simplified acid mine drainage scenarios, the strong impact of chemical speciation on the complete measurement uncertainty budget of geochemical modelling predictions is shown. The complete measurement uncertainty budget in combination with other metrological concepts like traceability is an essential element of quality assurance for experimental data. The elements of quality assurance are provided by international agreements and normative documents on national and international levels. The following discussion will focus on some metrological issues of sorption data.

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Section: Discussionmentioning

confidence: 99%

Am³⁺-F^- Interaction in Mixed System of Dimethyl Sulfoxide and Water

et al. 1997

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Americium / Mixed solvent / Stability constant / Monofluoride complex / Solvation number SummaryThe stability constant (/?,) of AmF 2+ in the mixed solvent system of dimethyl sulfoxide and water with 0.1 moldm -3 ionic strength was determined using a solvent extraction technique to compare with Nd(III) bearing similar chemical properties to Am(III). The value of In ß, was nearly constant when the mole fraction of DMSO in the bulk solution (X s ) was less than 0.04 and it increased with an increase in X a in the range of 0.04 < X s < 0.25. The variation of In β, with X x is obviously different from the result of Nd(III). The difference between the variations of In β, of Am(III) and Nd(III) with X, could be associated with (1) the cation solvation effect (containing the variation effect of the solvation number in the primary solvation sphere of tripositive cation) and (2) the variation effect of interionic distance between tripositive cation and fluoride ion. The variation of In β, of Am(IIl) in 0.04 < X, < 0.25 of the DMS0-H 2 0 system is considerably influenced by both effects due to the variation of solvation number in the primary solvation sphere and the variation of interionic distance, but that of Nd(III) in X, < 0.28 hardly contains those effects.

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A literature survey of mineral-specific sorption data on radionuclides with relevance to the disposal of radioactive waste

Cited by 6 publications

References 13 publications

Chemometric and Statistical Analysis of Uranium(VI) Hydrolysis at Elevated U(VI) Concentrations

Chemometric and Statistical Analysis of Uranium(VI) Hydrolysis at Elevated U(VI) Concentrations

Sorption of Iron on Surfaces: Modelling, Data Evaluation, and Measurement Uncertainty

Am³⁺-F^- Interaction in Mixed System of Dimethyl Sulfoxide and Water

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A literature survey of mineral-specific sorption data on radionuclides with relevance to the disposal of radioactive waste

Cited by 6 publications

References 13 publications

Chemometric and Statistical Analysis of Uranium(VI) Hydrolysis at Elevated U(VI) Concentrations

Chemometric and Statistical Analysis of Uranium(VI) Hydrolysis at Elevated U(VI) Concentrations

Sorption of Iron on Surfaces: Modelling, Data Evaluation, and Measurement Uncertainty

Am3+-F- Interaction in Mixed System of Dimethyl Sulfoxide and Water

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Am³⁺-F^- Interaction in Mixed System of Dimethyl Sulfoxide and Water