Formation of Outer- and Inner-Sphere Complexes of Lanthanide Elements at Montmorillonite-Water Interface

Takahashi, Yoshio; Tada, Akisa; Kimura, Takaumi; Shimizu, Hiroshi

doi:10.1246/cl.2000.700

Cited by 16 publications

(12 citation statements)

References 12 publications

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“…Initially, the sorption of Eu(III) on silica was studied. Similar experiments were conducted with other REE to examine the dependence of the sorption reaction on the ionic radii, which is related to the REE species at the solid-water interface [7][8][9]. Characterization of Eu(III) species at the interface was also conducted by laser-induced fluorescence spectroscopy (LIF), and some results from this technique have already been reported by Takahashi et al [10].…”

Section: Introductionmentioning

confidence: 87%

Interaction of Eu(III) ion and non-porous silica: Irreversible sorption of Eu(III) on silica and hydrolysis of silica promoted by Eu(III)

Takahashi¹,

Murata²,

Kimura³

2006

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 87%

Interaction of Eu(III) ion and non-porous silica: Irreversible sorption of Eu(III) on silica and hydrolysis of silica promoted by Eu(III)

Takahashi¹,

Murata²,

Kimura³

2006

Journal of Alloys and Compounds

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“…It was observed that the Kd values increased with the pH in the pH range examined, as suggested from various studies. [6][7][8][9][10] In the log Kd patterns, the slope of the pattern against Z (atomic number) also increased with the pH above pH 5. In this study, we tried to extract REE species sorbed on montmorillonite from REE distribution data.…”

Section: Ree Species Sorbed On Montmorillonite and The Slope Of Ree Pmentioning

confidence: 96%

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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“…The comparison with the empirical relationships proposed for Eu(III) [51][52] can be very difficult in the case of humic complexation because of the unknown origin of the bi-exponential decay, and because of the necessity to obtain the relation for the particular system [60]. Two hypotheses can be made: (i) the mono-exponential decay provide an average comportment of Eu(III)-HS complex, and (ii) one can consider that the bi-exponential decay is related to two different emitting species, then one can estimate the remaining hydration of the second decay which could be viewed as a complex hindered from OH quenching.…”

Section: Evolution Of the Decay Timesmentioning

confidence: 99%

Spectral and temporal luminescent properties of Eu(III) in humic substance solutions from different origins

Brevet

Claret

Reiller

2009

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Although a high heterogeneity of composition is awaited for humic substances, their complexation properties do not seem to greatly depend on their origins. The information on the difference in the structure of these complexes is scarce. To participate in the filling of this lack, a study of the spectral and temporal evolution of the Eu(III) luminescence implied in humic substance (HS) complexes is presented. Seven different extracts, namely Suwannee River fulvic acid (SRFA) and humic acid (SRHA), and Leonardite HA (LHA) from the International Humic Substances Society (USA), humic acid from Gorleben (GohyHA), and from the Kleiner Kranichsee bog (KFA, KHA) from Germany, and purified commercial Aldrich HA (PAHA), were made to contact with Eu(III). Eu(III)-HS time-resolved luminescence properties were compared with aqueous Eu(3+) at pH 5. Using an excitation wavelength of 394 nm, the typical bi-exponential luminescence decay for Eu(III)-HS complexes is common to all the samples. The components tau(1) and tau(2) are in the same order of magnitude for all the samples, i.e., 40 (7)F(2) transition exhibits the most striking differences. A slight blue shift is observed compared to aqueous Eu(3+) (lambda(max) = 615.4 nm), and the humic samples share almost the same lambda(max) approximately 614.5 nm. The main differences between the samples reside in a shoulder around lambda approximately 612.5 nm, modelled by a mixed Gaussian-Lorentzian band around lambda approximately 612 nm. SRFA shows the most intense shoulder with an intensity ratio of I(612.5)/I(614.7) = 1.1, KFA/KHA/SRHA share almost the same ratio I(612.5)/I(614.7) = 1.2-1.3, whilst the LHA/GohyHA/PAHA group has a I(612.5)/I(614.5) = 1.5-1.6. This shows that for the two groups of complexes, despite comparable complexing properties, slightly different symmetries are awaited.

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Formation of Outer- and Inner-Sphere Complexes of Lanthanide Elements at Montmorillonite-Water Interface

Cited by 16 publications

References 12 publications

Interaction of Eu(III) ion and non-porous silica: Irreversible sorption of Eu(III) on silica and hydrolysis of silica promoted by Eu(III)

Interaction of Eu(III) ion and non-porous silica: Irreversible sorption of Eu(III) on silica and hydrolysis of silica promoted by Eu(III)

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

Spectral and temporal luminescent properties of Eu(III) in humic substance solutions from different origins

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