The location of europium in Eu3+-exchanged zeolite-Y as determined by extended X-ray absorption fine structure (EXAFS) investigations at 77 K

Berry, Frank J.; Carbucicchio, M.; Chiari, Alessandra; Johnson, Craig; Moore, Elaine; Mortimer, Michael; Vetel, Frederic F. F.

doi:10.1039/b002820g

Cited by 17 publications

(22 citation statements)

References 12 publications

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“…We assumed that q = 7 for Gd 3 + ions inside the supercages of the hydrated zeolites. This is supported by extended X-ray absorption fine structure (EXAFS) investigations on Eu 3 + -exchanged zeolite Y; [17] the results showed that one oxygen atom of the framework is coordinated to Eu 3 + . A q value of 7 therefore results in an overall coordination number of 8 for Gd 3 + .…”

Section: Resultsmentioning

confidence: 73%

Gadolinium(III)‐Loaded Nanoparticulate Zeolites as Potential High‐Field MRI Contrast Agents: Relationship Between Structure and Relaxivity

Csajbók

Bányai

Elst

et al. 2005

Chemistry A European J

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The effects of dealumination, pore size, and calcination on the efficiency (as expressed in the relaxivity) of Gd3+-loaded zeolites for potential application as magnetic resonance imaging (MRI) contrast agents were studied. Partial dealumination of zeolites NaY or NaA by treatment with (NH4)2SiF6 or diluted HCl resulted in materials that, upon loading with Gd3+, had a much higher relaxivity than the corresponding non-dealuminated materials. Analysis of the 1H NMR dispersion profiles of the various zeolites showed that this can be mainly ascribed to an increase of the amount of water inside the zeolite cavities as a result of the destruction of walls between cavities. However, the average residence time of water inside the Gd3+-loaded cavities did not change significantly, which suggests that the windows of the Gd3+-loaded cavities are not affected by the dealumination. Upon calcination, the Gd3+ ions moved to the small sodalite cavities and became less accessible for water, resulting in a decrease in relaxivity. The important role of diffusion for the relaxivity was demonstrated by a comparison of the relaxivity of Gd3+-loaded zeolite NaY and NaA samples. NaA had much lower relaxivities due to the smaller pore sizes. The transversal relaxivities of the Gd3+-doped zeolites are comparable in magnitude to the longitudinal ones at low magnetic fields (<60 MHz). However at higher fields, the transversal relaxivities steeply increased, whereas the longitudinal relaxivities decreased as field strength increased. Therefore, these materials have potential as T1 MRI contrast agents at low field, and as T2 agents at higher fields.

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Section: Resultsmentioning

confidence: 73%

Gadolinium(III)‐Loaded Nanoparticulate Zeolites as Potential High‐Field MRI Contrast Agents: Relationship Between Structure and Relaxivity

Csajbók

Bányai

Elst

et al. 2005

Chemistry A European J

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“…The luminescence data show that Eu 3+ ions intercalated in the zeolite Y have the coordination num- ber 9 and are fully coordinated by water molecules [19]. On the other hand, Berry et al [26] concluded, based on X-ray absorption data, that Eu 3+ cations in zeolite Y sample modified at 60 • C are directly bound to the framework oxygens. The results of Chen et al [20] concerning the adsorption isotherm of La on the zeolite Y support the idea about the participation of framework oxygens in the coordination of La.…”

Section: Tetrad Effect In the Lanthanides Adsorptionmentioning

confidence: 95%

“…Finally, we would like to emphasize that the ion-exchange of the lanthanides on the zeolite Y was investigated by many scientists [19][20][21][22][23][24][25][26], but there is a lack of information concerning the change of their adsorption behavior in the whole lanthanide series; only selected lanthanides are inspected. In connection with this, our work is the first systematic investigation of the adsorption of all lanthanides on the zeolite Y, except for Pm.…”

Section: Introductionmentioning

confidence: 99%

Tetrad effect in the adsorption of the lanthanides on zeolite Y

Gładysz–Płaska

Majdan

Pikus

et al. 2007

Journal of Colloid and Interface Science

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“…In addition, systems of SDS micelles with lanthanide ions have been used for studying magnetic field effects on geminate pair recombination of radicals [5], or photoinduced emulsion polymerization [6] and are also of increasing interest in relation to the mesomorphism of lanthanide salts of anionic amphiphiles for applications in materials [7,8]. Lanthanides incorporated in suitable mesoporous materials also show considerable potential for catalysis [9].…”

Section: Introductionmentioning

confidence: 99%

Effect of terbium(III) chloride on the micellization properties of sodium decyl- and dodecyl-sulfate solutions

Neves

Valente

Burrows

et al. 2007

Journal of Colloid and Interface Science

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The effect of TbCl 3 on the aggregation processes of the anionic surfactants sodium decyl sulfate (SDeS) and sodium dodecyl sulfate (SDS) has been investigated. Electrical conductivity data, combined with Tb(III) luminescence measurements suggest that the formation of micelles involving TbCl 3 and SDS occurs at concentrations below the critical micelle concentration (cmc) of the pure surfactants; the formation of these mixed aggregates was also monitored by light scattering, which indicates that the addition of TbCl 3 to surfactant concentration at values below the pure surfactant cmc results in a much greater light scattering than that found with pure sodium alkylsulfate surfactant micelles. This phenomenon is dependent upon the alkyl chain length of the surfactant. With Tb(III)/DS − , complexes are formed with a cation/anion binding ratio varying from 3 to 6, which depends upon the initial concentration of Tb(III). This suggests that the majority of the cation hydration water molecules can be exchanged by the anionic surfactant. When the carbon chain length decreases, interactions between surfactant and Tb(III) also decrease, alterations in conductivity and fluorescence data are not so significant and, consequently, no binding ratio can be detected even if existing. The surfactant micellization is dependent on the presence of electrolyte in solution with apparent cmc being lower than the corresponding cmc value of pure SDS.

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The location of europium in Eu3+-exchanged zeolite-Y as determined by extended X-ray absorption fine structure (EXAFS) investigations at 77 K

Cited by 17 publications

References 12 publications

Gadolinium(III)‐Loaded Nanoparticulate Zeolites as Potential High‐Field MRI Contrast Agents: Relationship Between Structure and Relaxivity

Gadolinium(III)‐Loaded Nanoparticulate Zeolites as Potential High‐Field MRI Contrast Agents: Relationship Between Structure and Relaxivity

Tetrad effect in the adsorption of the lanthanides on zeolite Y

Effect of terbium(III) chloride on the micellization properties of sodium decyl- and dodecyl-sulfate solutions

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