Inner-sphere, outer-sphere and ternary surface complexes: a TRLFS study of the sorption process of Eu(III) onto smectite and kaolinite

Stumpf, Thorsten; Bauer, Andreas; Coppin, Frédéric; Fanghänel, Thomas; Kim, Jae-Il

doi:10.1524/ract.2002.90.6.345

Cited by 111 publications

(95 citation statements)

References 21 publications

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“…The major doublet, with average Mössbauer parameters of δ = 0.32 mm/s and = 0.60 mm/s for Ca-bentonite, was assigned to Fe 3+ at the octahedral sites, while the minor doublet, with δ = 1.07 mm/s and = 2.64 mm/s for Ca-bentonite, was attributed to Fe 2+ being at the octahedral sites in montmorillonite; these data are in good agreement with previous literature data for the montmorillonites [3][4][5][6]. We have found no essential differences between the room temperature Mössbauer spectra (Fig.…”

Section: Resultssupporting

confidence: 91%

“…The occurrence of rare earths in several products can improve their applicability due to advantageous properties of lanthanoides like unique electron con-figuration, fluorescence, high refractive index, high magnetic anisotropy, high electrical conductivity and high oxygen storage and release capacity. The exchange of the interlayer cations of montmorillonite with the ions of rare earth elements is an effective approach to obtain catalysts, catalyst supports, sensors and adsorbents [4][5][6]. Mössbauer spectroscopy has been widely applied [7][8][9] to study the microenvironments of iron atoms occurring in montmorillonite.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic sublattices in Np2Co17 and Np2Ni17

et al. 2016

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Novel montmorillonites were prepared by the exchange of the interlayer cations with a series of rare earth cations (La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, and Er) and characterized by XRD, XRF, SEM, chemical analysis and 57 Fe Mössbauer spectroscopy. An unexpected magnetically split component, assigned to iron being in the interlayer space, was observed in the Mössbauer spectra at 78K in some rare earth cation exchanged montmorillonite. This paper is the initial report about this observation. The transition of iron from the octahedral site to the interlayer and possible incorporation of rare earths in sites different from those which are in the interlayer space was concluded.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Magnetic sublattices in Np2Co17 and Np2Ni17

et al. 2016

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“…42 Similar results were also obtained by Stumpf et al for Eu(III) and Cm(III) by LIF. 45,46 The consistency between the spectroscopic data and the sorbed species estimated from the REE patterns strongly suggests that the REE patterns can be used for estimating the REE species at the solid-water interface.…”

Section: Comparison With Spectroscopic Datamentioning

confidence: 87%

Distribution Pattern of Rare Earth Ions between Water and Montmorillonite and Its Relation to the Sorbed Species of the Ions

2004

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Speciation is important for describing chemical reactions in the environment and for estimating the environmental behavior of metal ions. For REE and actinides(III), particulate matter can be the main carrier governing their migration in a natural aquifer in addition to complexed species in an aqueous phase. [1][2][3] However, the chemical species of REE or actinides(III) at a solid-water interface is still not clearly understood on a molecular scale. Although the complexed species in an aqueous phase can be easily assessed by solution chemistry data, 3,4 the complex nature of particulate matter often prevents us from precisely describing the sorption reaction of REE, or actinides(III). Regarding this point, the REE distribution patterns plotting the distribution coefficients between the solid and aqueous phases in the order of atomic number could be a clue to clarify the REE species at the solid-water interface, since the REE distribution patterns reflect the chemical species of REE at the solid-water interface due to a systematic variation of the chemical character across the REE series. In this study, we investigated the possibility of using the REE distribution patterns to estimate the species of REE, or actinides(III), at a montmorillonite-water interface as an example of a solid-water system in a natural aquifer.It is considered that three features in the REE (including Y) patterns can be useful to estimate the REE species at the solidwater interface: (1) the slope of the REE pattern, (2) the tetrad effect, and (3) the Y/Ho ratio, the details of which are described in the next section. Although the sorption of selected REE on montmorillonite has been studied, [5][6][7][8] there have been few studies on the sorption of a complete REE series where REE patterns are employed to estimate the sorbed species, despite that REE patterns are highly relevant to the REE species. A part of the results were presented in Takahashi et al., but Y data were not included. 9 A similar aspect was also presented by Coppin et al., suggesting a correlation between the slope of the REE pattern and the REE species sorbed on clay minerals. 10 However, Coppin et al. have not clearly referred to the effectiveness of using the tetrad effect or the Y/Ho ratio for REE speciation, which is discussed in the present study. 10 Here, it is reported that the variation of the REE patterns is closely correlated with structural information on REE at the montmorillonite-water interface. In addition, the variation of the REE distribution patterns in the presence of humic acid was also included in this paper. Humic acid is another important constituent in a natural aquifer that can influence the REE behavior in the hydrosphere. [11][12][13][14] The relation between the REE patterns and the REE species at the solid-water interface was consistent with spectroscopic data obtained by laser-induced fluorescence for Eu(III) and Cm(III) species at the solid-water interface. These REE (rare earth element) distribution coefficients (Kd) between the aqueous p...

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“…For lanthanide/actinide carbonate-clay mineral systems, no reliable thermodynamic and structural data are available. A TRLFS study by Stumpf (2002) [22] underlined the possibility that ternary carbonato surface complexes are formed for Eu(III) on smectite and kaolinite under air equilibrated conditions. The evidence is based on the differences observed in the fluorescence spectra and fluorescence emission lifetimes of sorbed Eu(III) in the presence and absence of carbonate.…”

Section: Resultsmentioning

confidence: 99%

“…The cation exchange capacity CEC, determined using the 22 Na isotopic dilution method was 0.870 ± 0.035 eq kg −1 [16,17].…”

Section: Experimental 31 Materialsmentioning

confidence: 99%

The influence of carbonate complexation on lanthanide/actinide sorption on montmorillonite

Fernandes¹,

Baeyens

Bradbury

2008

Radiochimica Acta

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Actinide surface complexation / Carbonate complexation / Montmorillonite / Sorption modellingSummary. The safety case for radioactive waste repositories is, to a large extend based on the physical and chemical retention of radionuclides on clay minerals which are important constituents in both the man-made engineered barriers and in argillaceous host rock formations. The presence of carbonate, one of the most important inorganic ligands for lanthanide and actinide ions in groundwaters and clay porewaters, can have a significant influence on their sorption behaviour on clay minerals. The sorption of Eu(III) on Na-montmorillonite in the absence and the presence of carbonate was investigated in batch sorption experiments. In the presence of carbonate two sets of experimental conditions were investigated. Eu(III) sorption measurements were performed as a function of pH in equilibrium with atmospheric p CO 2 (= 10 −3.5 bar) and at a variable p CO 2 (= 10 −1.4 to 10 −3.4 bar). The sorption data were modelled using the 2 site protolysis non-electrostatic surface complexation and cation exchange model. Both experimental data sets in the presence of carbon could be quantitatively modelled by including in the sorption model two additional surface complexation reactions on the strong sites forming ≡S S OEuCO 3 0 and ≡S S OEuOHCO 3 − surface complexes.

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Inner-sphere, outer-sphere and ternary surface complexes: a TRLFS study of the sorption process of Eu(III) onto smectite and kaolinite

Cited by 111 publications

References 21 publications

Magnetic sublattices in Np2Co17 and Np2Ni17

Magnetic sublattices in Np2Co17 and Np2Ni17

Distribution Pattern of Rare Earth Ions between Water and Montmorillonite and Its Relation to the Sorbed Species of the Ions

The influence of carbonate complexation on lanthanide/actinide sorption on montmorillonite

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