Kinetic behavior of water as migration media in compacted montmorillonite using H218O and applying electric potential gradient

Tanaka, Shingo; Noda, N.; Higashihara, Tomohiro; Sato, Shunsuke; Kozaki, Tamotsu; Sato, Haruo; Hatanaka, Koichiro

doi:10.1016/j.pce.2008.10.043

Cited by 5 publications

(4 citation statements)

References 17 publications

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“…The H 2 18 O was measured by isotope ratio mass spectrometry (IR-MS). Detailed procedures used to measure the H 2 18 O were described by Tanaka et al 15 Fig. 1 Experimental apparatus for applying a constant current.…”

Section: Materials and Experimental Methodsmentioning

confidence: 99%

“…This view is suggested in a previous work; the dispersion of electrically neutral helium under an electric potential gradient is considerably greater than that of water using H 2 18 O as a tracer. 15) It is very likely that chloride ions tend to migrate outside the stacks. In this case, the effect of water flow on the Cl À ions will be stronger than that expected when using an average water mobility (Eq.…”

Section: Mobility and The Einstein Relationmentioning

confidence: 99%

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Electrokinetic Study of Migration of Anions, Cations, and Water in Water-Saturated Compacted Sodium Montmorillonite

Tanaka

Noda

Sato

et al. 2011

J. Nucl. Sci. Technol.

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Electromigration studies of 36 Cl À ions and 22 Na þ ions, and electro-osmosis of water traced with HTO and H 2 18 O were conducted with water-saturated compacted sodium montmorillonite having dry densities from 0.8 to 1.6 Mg/m 3. The mobilities and dispersivities for each species were obtained from the apparent electromigration velocities and hydrodynamic dispersion coefficients, respectively. When corrected by water flow, the apparent diffusion coefficients of Cl À ions obtained from the Einstein relation are in good agreement with the coefficients obtained from an earlier conventional diffusion experiment in the high dry densities (above 1.3 Mg/m 3). This result suggests that the migration pathways of Cl À ions are nearly identical to those of water above 1.3 Mg/m 3. The former diffusion coefficient is smaller than the latter in the low dry densities (below 1.3 Mg/m 3), suggesting that Cl À ions migrate in the region distant from the montmorillonite sheets. In contrast, for Na þ ions, the obtained D a values without water flow correction are in good agreement with conventional values at all dry densities. This suggests that Na þ ions migrate mainly in the interlayer and the vicinity of montmorillonite sheets. The dispersivities increase with increasing dry densities for all species. This corresponds to a geometrical complexity that increases with increasing dry density.

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Section: Materials and Experimental Methodsmentioning

confidence: 99%

Section: Mobility and The Einstein Relationmentioning

confidence: 99%

Electrokinetic Study of Migration of Anions, Cations, and Water in Water-Saturated Compacted Sodium Montmorillonite

Tanaka

Noda

Sato

et al. 2011

J. Nucl. Sci. Technol.

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“…As previously reported, the dispersivities of electrically neutral dissolved helium were classified from 1 Â 10 À3 to 1 Â 10 À2 m, those of H 2 18 O were classified from 1 Â 10 À4 to 1 Â 10 À3 m, and those of Na þ ions were classified from 1 Â 10 À5 to 1 Â 10 À4 m in compacted montmorillonite under an electric potential gradient. 15,21,31) These reports also concluded that these classifications of dispersivities result from the existence of two kinds of water flow; one is electro-osmotic flow in the pore space and the other is the flow of solvated water molecules accompanied by Na þ migration in the interlayer under an electric potential gradient. Anions were also reported to have higher tortuosities than cations and water in clayey materials.…”

Section: Mechanical Dispersion and Dispersivitymentioning

confidence: 95%

Section: Mobility and The Einstein Relationmentioning

confidence: 99%

Electrokinetic Study of Migration of Anions, Cations, and Water in Water-Saturated Compacted Sodium Montmorillonite

Tanaka

Noda

Sato

et al. 2011

Journal of Nuclear Science and Technology

Self Cite

View full text Add to dashboard Cite

Electromigration studies of 36 Cl À ions and 22 Na þ ions, and electro-osmosis of water traced with HTO and H 2 18 O were conducted with water-saturated compacted sodium montmorillonite having dry densities from 0.8 to 1.6 Mg/m 3 . The mobilities and dispersivities for each species were obtained from the apparent electromigration velocities and hydrodynamic dispersion coefficients, respectively. When corrected by water flow, the apparent diffusion coefficients of Cl À ions obtained from the Einstein relation are in good agreement with the coefficients obtained from an earlier conventional diffusion experiment in the high dry densities (above 1.3 Mg/m 3 ). This result suggests that the migration pathways of Cl À ions are nearly identical to those of water above 1.3 Mg/m 3 . The former diffusion coefficient is smaller than the latter in the low dry densities (below 1.3 Mg/m 3 ), suggesting that Cl À ions migrate in the region distant from the montmorillonite sheets. In contrast, for Na þ ions, the obtained D a values without water flow correction are in good agreement with conventional values at all dry densities. This suggests that Na þ ions migrate mainly in the interlayer and the vicinity of montmorillonite sheets. The dispersivities increase with increasing dry densities for all species. This corresponds to a geometrical complexity that increases with increasing dry density.

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Combined tracer through-diffusion of HTO and 22Na through Na-montmorillonite with different bulk dry densities

Bestel

Glaus

Frick

et al. 2018

Applied Geochemistry

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Kinetic behavior of water as migration media in compacted montmorillonite using H218O and applying electric potential gradient

Cited by 5 publications

References 17 publications

Electrokinetic Study of Migration of Anions, Cations, and Water in Water-Saturated Compacted Sodium Montmorillonite

Electrokinetic Study of Migration of Anions, Cations, and Water in Water-Saturated Compacted Sodium Montmorillonite

Electrokinetic Study of Migration of Anions, Cations, and Water in Water-Saturated Compacted Sodium Montmorillonite

Combined tracer through-diffusion of HTO and 22Na through Na-montmorillonite with different bulk dry densities

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