A Combined X-Ray Photoelectron and Auger Electron Spectroscopic Study of Cesium in Variable-Charge Montmorillonites

Dutta, N. C.; Iwasaki, Takashi; Ebina, Takeo; Hayashi, Hiromichi

doi:10.1006/jcis.1999.6291

Cited by 15 publications

(5 citation statements)

References 26 publications

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“…[13,14] Although simulations of montmorillonite to Na + or K + have been conducted, [15][16][17][18][19][20] no simulation study has taken into consideration the questions of how and to what extent the presence of Cs + cations affect the swelling pattern of a natural Na-rich montmorillonite and why the swelling patterns of Na-rich/Cs-poor or Cs-rich montmorillonites are very different from those of Na-saturated montmorillonite. In previous simulations [21][22][23][24][25] with a Cs-rich Wyoming-type montmorillonite, containing Na + and K + in the interlayer spaces, the layer spacings and the adsorption of cations were observed experimentally to be very different from those typically for an Na-saturated montmorillonite. Experimental studies have shown that the adsorption rate decreases in the presence of coexistent Na + and K + ions.…”

Section: Introductionmentioning

confidence: 86%

A molecular dynamics study of the swelling patterns of Na/Cs-montmorillonites and the hydration of interlayer cations

Liu¹,

Chen²

2013

Chinese Phys. B

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We report on a molecular dynamics study of the swelling patterns of an Na-rich/Cs-poor montomorillonite and a Csmontomorillonite. The recently developed CLAYFF force field is used to predict the basal spacing as a function of the water content in the interlayer. The simulations reproduce the swelling patterns of the Na and Cs-montomorillonite, suggesting a mechanism of its hydration different from that of the montomorillonite. In addition, we find that the differences in size and hydration energy of Na and Cs ions have strong implications for the structure and the internal energy of interlayer water. In particular, our results indicate that the hydrate difference in the presence of coexistent Na and Cs has a larger influence on the behavior of a clay-water system. For Na-rich/Cs-poor montomorillonite, the hydration energy values of Na ions and water molecules each have a dramatic increase compared with those in Na-montomorillonite on the interlayer spacing, and the hydration energy values of Cs ions and water molecules decrease somewhat compared with those in Cs-montomorillonite.

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Section: Introductionmentioning

confidence: 86%

A molecular dynamics study of the swelling patterns of Na/Cs-montmorillonites and the hydration of interlayer cations

Liu¹,

Chen²

2013

Chinese Phys. B

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“…XPS is an inherent surface sensitive technique that has been applied in various studies for qualitative and quantitative characterization of sorption [24][25][26][27][28][29][30]. In this work, the XPS measurements were used to elucidate the elemental contents of the natural and Sr-sorbed mineral samples.…”

Section: Characterization Of the Sr 2+ -Sorbed Mineralsmentioning

confidence: 99%

Characterization of Sr²⁺uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

Shahwan¹,

Erten²

2005

Radiochimica Acta

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Sr2+ / Kaolinite / Magnesite Summary. The sorption behavior of Sr 2+ ions on natural minerals rich in kaolinite and magnesite was studied using SEM/EDS, XPS, XRPD, AAS/AES and DRIFT techniques. Quantitative analysis of the XPS data shows that magnesite is more effective in Sr 2+ uptake than kaolinite. DRIFT spectra and XRPD patterns indicate that the structures of both minerals were not affected upon Sr 2+ sorption. Intercalation of DMSO in kaolinite lamellae aiming at increasing the interlayer space did not significantly enhance the sorption capacity of the clay towards Sr 2+ probably due to the lack of a negative charge on the accessible sites. EDS mapping indicated that while the sorbed Sr is equally distributed on surface of natural kaolinite, it was associated -to a larger extent -with the regions richer in Mg in the case of natural magnesite. Comparing the uptake mechanisms of natural magnesite with that of pure MgCO 3 , it was seen that while natural magnesite sorbed Sr 2+ mainly through an ion exchange type mechanism, the formation of SrCO 3 coprecipitate was detected on the surface of the MgCO 3 at higher loadings.

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“…Moreover, the lower binding energy for Prrenjas sample can be attributed to the higher d 001 spacing when compared to Wyoming Mg-montmorillonite (Dutta et al, 1999).…”

Section: Xps Analysismentioning

confidence: 98%

Incidence of lead uptake on the microstructure of a (Mg, Ca)-bearing bentonite (Prrenjas, Albania)

Jozja¹,

Baillif²,

Touray³

et al. 2006

ejm

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The article addresses Pb uptake and microstructural/morphological modifications of a (Mg, Ca) bentonite (Prrenjas, Albania) after interaction with solutions of elevated lead content. Comparison is made with a Wyoming montmorillonite transformed to the Mg-dominated form. Characterized by X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) the Prrenjas bentonite is predominantly a smectite, containing 10% of interlayered illite, with associated kaolinite, antigorite, halloysite and minor chlorite. Significant magnesium is present in the octahedral layer in association with aluminium and iron. The CEC is rather high (above 80 meq/100g). Magnesium and calcium are the main cations exchanged during CEC determinations and Pb uptake experiments. From TEM studies, microstructural units are composed by closely packed clay particles with 10 to15 stacked platelets, in contrast with Wyoming montmorillonite. Exchange experiments with lead nitrate on suspended clays, have been performed with concentrations ranging from 10-5 M to 10-2 M. A comparable capacity of lead sorption is observed by Atomic Absorption Spectrometry (AAS) for Prrenjas bentonite and Wyoming montmorillonite. At increasing lead uptake, a higher reduction of hydration in interlayer space is observed by XRD on Wyoming montmorillonite. At the highest lead concentrations, X-ray Photoelectron Spectroscopy (XPS) analyses of the Prrenjas Bentonite reveal Pb sorption in a "non interlayer" site. TEM images of the same clay show an important size decreasing of microstructural units in relation to the lead sorption. On the contrary, the Mg-Wyoming montmorillonite is not modified. Presumably, the "non interlayer lead" uptake results either from surface complexation at an edge site or from ionic exchange with edge-exposed octahedral magnesium. Both mechanisms could initiate at edge-to-face contacts and result in a breaking process of the microstructural units

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A Combined X-Ray Photoelectron and Auger Electron Spectroscopic Study of Cesium in Variable-Charge Montmorillonites

Cited by 15 publications

References 26 publications

A molecular dynamics study of the swelling patterns of Na/Cs-montmorillonites and the hydration of interlayer cations

A molecular dynamics study of the swelling patterns of Na/Cs-montmorillonites and the hydration of interlayer cations

Characterization of Sr²⁺uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

Incidence of lead uptake on the microstructure of a (Mg, Ca)-bearing bentonite (Prrenjas, Albania)

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A Combined X-Ray Photoelectron and Auger Electron Spectroscopic Study of Cesium in Variable-Charge Montmorillonites

Cited by 15 publications

References 26 publications

A molecular dynamics study of the swelling patterns of Na/Cs-montmorillonites and the hydration of interlayer cations

A molecular dynamics study of the swelling patterns of Na/Cs-montmorillonites and the hydration of interlayer cations

Characterization of Sr2+uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT

Incidence of lead uptake on the microstructure of a (Mg, Ca)-bearing bentonite (Prrenjas, Albania)

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Characterization of Sr²⁺uptake on natural minerals of kaolinite and magnesite using XRPD, SEM/EDS, XPS, and DRIFT