Comparative study of self-diffusion of the trivalent ions Eu3+(4f) and Am3+ in aqueous solutions

Latrous, H.; Ammar, M.; M'halla, Jalel; Oliver, J. H.; Chemla, M.

doi:10.1016/s0020-1693(00)94623-1

Cited by 4 publications

(7 citation statements)

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“…Table 3 lists radionuclide-specific transport properties. The molecular diffusion coefficient in bulk water for the radionuclides of interest can be calculated using the Stokes-Einstein law [75] or determined experimentally [76][77][78][79]. During the simulation, an effective diffusion coefficient is dynamically calculated to account for temperature effects and the impacts of salinity on viscosity according to the Stokes-Einstein equation [75].…”

Section: Processes and Parametersmentioning

confidence: 99%

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Post-Closure Safety Analysis of Nuclear Waste Disposal in Deep Vertical Boreholes

Finsterle¹,

Muller

Grimsich

et al. 2021

Energies

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Isolation of spent nuclear fuel assemblies in deep vertical boreholes is analyzed. The main safety features of the borehole concept are related to the repository’s great depth, implying (a) long migration distances and correspondingly long travel times, allowing radionuclides to decay, (b) separation of the repository from the dynamic hydrological cycle near the land surface, (c) stable geological and hydrogeological conditions, and (d) a geochemically reducing environment. An integrated simulation model of the engineered and natural barrier systems has been developed to examine multiple scenarios of the release of radionuclides from the waste canisters, the transport through a fractured porous host rock, and the extraction of potentially contaminated drinking water from an aquifer. These generic simulations include thermal effects from both the natural geothermal gradient and the heat-generating waste, the influence of topography on regional groundwater flow, moderated by salinity stratification at depth, and the role of borehole sealing. The impact of these processes on the transport of select radionuclides is studied, which include long-lived, soluble, sorbing or highly mobile isotopes along with a decay chain of safety-relevant actinide metals. The generic analyses suggest that a deep vertical borehole repository has the potential to be a safe option for the disposal of certain waste streams, with the depth itself and the stable hydrogeological environment encountered in the emplacement zone providing inherent long-term isolation, which allows for reduced reliance on a complex engineered barrier system.

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Section: Processes and Parametersmentioning

confidence: 99%

“…Oxidation state at reducing Eh and pH between 7 and 9 2. Diffusion coefficient in bulk water at 25 • C[76][77][78][79] 3. Pessimistic K d -values from[81] Maximum solubility for granitic bedrock chemistries[11].…”

mentioning

confidence: 99%

Post-Closure Safety Analysis of Nuclear Waste Disposal in Deep Vertical Boreholes

Finsterle¹,

Muller

Grimsich

et al. 2021

Energies

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“…In the same context, the stability constant of europium nitrate 22 , berkelium nitrate 23 and lanthanides complex 24 were estimated. In this paper, we will justify our choice of using a pH value of 2.50 in order to avoid hydrolysis of trivalent 4f and 5f ions and to minimize the formation of ion pairs or complexes [6][7][25][26][27][28] . In dilute solutions, the hydrodynamic theory of Onsager may be used for the evaluation and interpretation of transport parameters 29 as a function of the ionic composition of the solution.…”

Section: Introductionmentioning

confidence: 99%

“…The ionic strength was used in preference to the molar concentration of gadolinium nitrate, owing to the presence of nitric acid in all the solutions. The limiting coefficient value, D 0, obtained by extrapolation of the measured values as a function of the ionic strength I, is compared to the limiting coefficient at infinite dilute solution taken from published conductimetric measurements 17,30 Bk (III) in the ionic transport process [6][7]25 . Therefore, it may be argued that 153 Gd (III) and the trivalent actinide ions have essentially the same degree of hydration as a tripositive ion of comparable ionic radii in the absence of hydrolysis, ion pairing or complexing at pH 2.50 31 .…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, it may be argued that 153 Gd (III) and the trivalent actinide ions have essentially the same degree of hydration as a tripositive ion of comparable ionic radii in the absence of hydrolysis, ion pairing or complexing at pH 2.50 31 . For dilute solutions, the variation of D with the square root of the supporting electrolyte solution concentration is not linear 5,7,[25][26][27] . …”

Section: Introductionmentioning

confidence: 99%

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Investigation of the Self-Diffusion Coefficients of Trivalent Gd3+ in aqueous solutions: The Effect of Hydrolysis and nitrate ion association

Besbes

Ouerfelli²,

Abderabba³

et al. 2012

Mediterr.J.Chem.,

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Abstract:In recent work, we have deduced that berkelium and gadolinium, which have 4f and 5f with half-filled configurations, also display similar diffusion properties. Results, using self-diffusion coefficients to study thermodynamic properties, show very similar behavior, which is understood given their similarities in charge, ionic size, mobility, conductance, and hydration number. In this paper we undertook a study of Gd 3+ as an aid for deducing the thermodynamics properties of the Bk 3+ .In first part we compare magnitudes of transport (self-diffusion coefficient) of the trivalent aquo ions of Gd III for two concentrations, C 1 = 2 10 -4 mol.L -1 , C 2 = 10 -3 mol.L -1 , and in perchlorate and nitrate media . In second part, The variation of D versus pH shows three zonesWe changed the NO 3 -counter ion with ClO 4 -,and found that measurements must be carried in perchloric acid medium so as to avoid pairing phenomena. Using association constants between Gd 3+ and NO 3 -, and a hydration constant, we estimated self-diffusion coefficients for Gd(NO 3 ) 2+ and Gd(OH) 2+ .The results justified our choice of working at pH = 2.5 which constitute an optimum condition to avoid hydrolysis and pairing phenomena. Our results were confirmed by mobility measurements using an electro migration technique.

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Ionic self-diffusion coefficients of (III) in solutions in water - dioxan mixtures at

Ouerfelli¹,

Ammar²,

Latrous³

1996

J. Phys.: Condens. Matter

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The measurement of ionic self-diffusion coefficients of the lanthanide ions (III) in asymmetrical electrolytes (3:1) solutions of in hydro-organic water - dioxan mixtures (at a low dielectric constant) gives evidence of the progressive association of ion pairs. The study of different physical - chemical properties in all the domains of composition shows the existence of three regions with distinct behaviours. The application of association theory to such an asymmetrical electrolyte (3:1) with a polyvalent cation enables us to delimit the validity of the Bjerrum and Fuoss theories.

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Comparative study of self-diffusion of the trivalent ions Eu3+(4f) and Am3+ in aqueous solutions

Cited by 4 publications

References 1 publication

Post-Closure Safety Analysis of Nuclear Waste Disposal in Deep Vertical Boreholes

Post-Closure Safety Analysis of Nuclear Waste Disposal in Deep Vertical Boreholes

Investigation of the Self-Diffusion Coefficients of Trivalent Gd3+ in aqueous solutions: The Effect of Hydrolysis and nitrate ion association

Ionic self-diffusion coefficients of (III) in solutions in water - dioxan mixtures at

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