Molecular dynamics simulation of the interaction of uranium (VI) with the C–S–H phase of cement in the presence of gluconate

Андронюк, Юлія; Kalinichev, Andrey G.

doi:10.1016/j.apgeochem.2019.104496

Cited by 23 publications

(18 citation statements)

References 79 publications

(92 reference statements)

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“…In total, six surface beryllium complexes were identified: three for Be(OH)4 2− (Be1-Be3) and three for Be(OH)3 − (Be4-Be6). The abundance of charge-compensating Ca 2+ ions creates multiple binding possibilities for anionic species, and the mediation role of Ca 2+ in the adsorption of highly hydrolyzed metal ions on C-S-H has been already proposed and discussed [33,48]. As it can be seen from Figure 4, all of the observed surface complexes involve at least one Ca 2+ cation coordinated with deprotonated silanol groups.…”

Section: Surface Complexation Of Be(ii) On C-s-h: Molecular Dynamics Studymentioning

confidence: 81%

“…For the complexes Be1 and Be2, Ca(OH) + was present in the second coordination sphere, increasing the total number of hydroxyl groups to five. On average, Be(OH)4 2− ions coordinate three Ca 2+ cations both as innersphere (Be1 and Be2) and outer-sphere (Be3) complexes, while Be(OH)3 − ions mostly coor- The abundance of charge-compensating Ca 2+ ions creates multiple binding possibilities for anionic species, and the mediation role of Ca 2+ in the adsorption of highly hydrolyzed metal ions on C-S-H has been already proposed and discussed [33,48]. As it can be seen from Figure 4, all of the observed surface complexes involve at least one Ca 2+ cation coordinated with deprotonated silanol groups.…”

Section: Surface Complexation Of Be(ii) On C-s-h: Molecular Dynamics Studymentioning

confidence: 99%

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Uptake of Be(II) by Cement in Degradation Stage I: Wet-Chemistry and Molecular Dynamics Studies

et al. 2021

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The uptake of beryllium by hardened cement paste (HCP, with CEM I 42,5 N BV/SR/LA type) in degradation stage I was investigated with a series of batch sorption experiments with 10−6 M ≤ [Be(II)]0 ≤ 10−2.5 M and 2 g·L−1 ≤ [S/L] ≤ 50 g·L−1. All experiments were performed under Ar atmosphere at T = (22 ± 2) °C. Solubility limits calculated for α-Be(OH)2(cr) in the conditions of the cement pore water were used to define the experimental window in the sorption experiments. Beryllium sorbs strongly on HCP under all of the investigated conditions, with log Rd ≈ 5.5 (Rd in Lkg−1). Sorption isotherms show a linear behavior with a slope of ≈ +1 (log [Be(II)]solid vs. log [Be(II)]aq) over four orders of magnitude (10−8 M ≤ [Be(II)]aq ≤ 10−4 M), which confirm that the uptake is controlled by sorption processes and that solubility phenomena do not play any role within the considered boundary conditions. The similar uptake observed for beryllium in calcium silicate hydrate (C-S-H) phases supports that the C-S-H phases are the main sink of Be(II) in cement. The strong uptake observed for Be(II) agrees with the findings reported for heavier metal ions, e.g., Zn(II), Eu(III), Am(III), or Th(IV). The exceptional sorption properties of beryllium can be partially explained by its small size, which result in a charge-to-size ratio (z/d) of the same order as Eu(III) or Am(III). Kinetic experiments confirm the slow uptake of Be(II), which is characterized by a two-step process. In analogy to other strongly sorbing metal ions such as Zn(II) or Th(IV), a fast surface complexation (t < 4 days) followed by a slower incorporation of Be(II) in the C-S-H structure (t ≥ 60 days) are proposed. The surface complexation was studied in detail with molecular dynamic simulations, and the most common surface species are identified and described. This work provides the first experimental evidence supporting the strong uptake of Be(II) by HCP in degradation stage I, further extending previous findings on C-S-H phases and HCP in degradation stage II. These results overcome previous conservative estimates assuming no or only a weak uptake in cementitious systems and represent a relevant contribution for the quantitative assessment on the retention/mobilization of beryllium in the context of nuclear waste disposal.

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Section: Surface Complexation Of Be(ii) On C-s-h: Molecular Dynamics Studymentioning

confidence: 81%

Section: Surface Complexation Of Be(ii) On C-s-h: Molecular Dynamics Studymentioning

confidence: 99%

Uptake of Be(II) by Cement in Degradation Stage I: Wet-Chemistry and Molecular Dynamics Studies

et al. 2021

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“…76,77 Even though classical approaches, such as Clayff, cannot model chemical reactions, they can still be successfully applied to simulate the systems at various equilibrium states, that is, before and after the reaction. Androniuk and Kalinichev 78 have recently applied this approach to develop a series of classical models for calcium silicate hydrates (C−S−H) corresponding to different Ca/Si ratios and different degrees of surface protonation, using experimental 29 Si MAS NMR data 79, 80 and accurate quantum chemical results 81 as guidance. The models were then successfully applied to simulate adsorption of uranyl ions at the hydrated C−S−H surfaces as a function of Ca/Si ratio and solution pH, to determine the effects of organic molecules, such as gluconate, on these adsorption and complexation processes, and to interpret the experimentally observed behavior of these systems on a fundamental atomistic scale.…”

Section: Applications Of Clayffmentioning

confidence: 99%

“…The models were then successfully applied to simulate adsorption of uranyl ions at the hydrated C−S−H surfaces as a function of Ca/Si ratio and solution pH, to determine the effects of organic molecules, such as gluconate, on these adsorption and complexation processes, and to interpret the experimentally observed behavior of these systems on a fundamental atomistic scale. 78 3.3. Layered Double Hydroxides.…”

Section: Applications Of Clayffmentioning

confidence: 99%

Advances in Clayff Molecular Simulation of Layered and Nanoporous Materials and Their Aqueous Interfaces

2021

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As a general-purpose force field for molecular simulations of layered materials and their fluid interfaces, Clayff continues to see broad usage in atomistic computational modeling for numerous geoscience and materials science applications due to its (1) success in predicting properties of bulk nanoporous materials and their interfaces, (2) transferability to a range of layered and nanoporous materials, and (3) simple functional form which facilitates incorporation into a variety of simulation codes. Here, we review applications of Clayff to model bulk phases and interfaces not included in the original parameter set and recent modifications for modeling surface terminations such as hydroxylated nanoparticle edges. We conclude with a discussion of expectations for future developments.

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“…A disturbance of uranium sorption in calcite free systems is expected within organic plumes through two antagonistic effects: on one hand the "decomplexation" of U(VI)/Ca/CO 3 2complexes due to free calcium depletion, and on the other hand, the formation of U(VI)-Organic complexes. Analogue effects are evidenced using molecular modelling approaches on cementitious materials by Androniuk and Kalinichev (2020), with gluconate forming stable complexes with Ca 2+ , thus promoting the substitution of Ca 2+ by Ca-uranyl complexes. Figure 7a shows the disturbance of [T.I.C.]…”

Section: Effect Of Media and U(vi) Sorption Mechanismmentioning

confidence: 99%

Effect of organic compounds on the retention of radionuclides in clay rocks: Mechanisms and specificities of Eu(III), Th(IV), and U(VI)

Fralova

Lefèvre

Madé

et al. 2021

Applied Geochemistry

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Molecular dynamics simulation of the interaction of uranium (VI) with the C–S–H phase of cement in the presence of gluconate

Cited by 23 publications

References 79 publications

Uptake of Be(II) by Cement in Degradation Stage I: Wet-Chemistry and Molecular Dynamics Studies

Uptake of Be(II) by Cement in Degradation Stage I: Wet-Chemistry and Molecular Dynamics Studies

Advances in Clayff Molecular Simulation of Layered and Nanoporous Materials and Their Aqueous Interfaces

Effect of organic compounds on the retention of radionuclides in clay rocks: Mechanisms and specificities of Eu(III), Th(IV), and U(VI)

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