Self-diffusion in nanopores studied by the NMR pulse gradient spin echo

Abstract Self-diffusion coefficients of dimethylether have been measured as a function of temperature (185-458 K) and pressure (up to 200 MPa) by pulse-gradient field spin-echo NMR. Calculated activation volumes (ΔV*) fall from 15 (10-6 m3/mole) at the highest temperature to 7 (10-6 m3/mole) at the lowest. This trend is in keeping with values for other non-associating liquids. Comparison with self diffusion data for propane and ethanol reveals that the translational diffusivity in dimethylether is influenced by the substance's modest dipole moment (1.3 Debye). The effect is small but measurable and becomes more pronounced at lower temperatures.

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The Measurement of Self-Diffusion Coefficients of Various Species by the Pulse Gradient-field Spin-Echo NMR Methd; The Motions of Ions in the Electrolytes for Lithium Batteries.

Materia Japan ◽

10.2320/materia.38.555 ◽

1999 ◽

Vol 38 (7) ◽

pp. 555-558

Author(s):

Kikuko Hayamizu ◽

Yuichi Aihara

Keyword(s):

Lithium Batteries ◽

Diffusion Coefficients ◽

Spin Echo ◽

Gradient Field ◽

Self Diffusion ◽

Pulse Gradient

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Pulse Gradient Spin Echo Measurement of Flow Dynamics in a Porous Structure: NMR Spectral Analysis of Motional Correlations

Magnetic Resonance in Colloid and Interface Science ◽

10.1007/978-94-010-0534-0_38 ◽

2002 ◽

pp. 433-444

Author(s):

Janez Stepišnik ◽

Aleš Mohorič ◽

Andrej Duh

Keyword(s):

Spectral Analysis ◽

Porous Structure ◽

Spin Echo ◽

Flow Dynamics ◽

Pulse Gradient

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Self- diffusion of H2O in stevensite gel: effects of temperature and clay fraction

Clay Minerals ◽

10.1180/0009855023710019 ◽

2002 ◽

Vol 37 (1) ◽

pp. 83-91 ◽

Cited By ~ 9

Author(s):

Y. Nakashima

Keyword(s):

Spin Echo ◽

Polymer Network ◽

Clay Fraction ◽

Weight Fraction ◽

Bulk Water ◽

Proton Nuclear Magnetic Resonance ◽

Exponential Dependence ◽

Self Diffusion ◽

Effects Of Temperature ◽

Characteristic Interval

AbstractSelf-diffusion coefficients of water molecules (1H2O) in Na-stevensite gel were measured by pulsed-gradient spin-echo (PGSE) proton nuclear magnetic resonance (NMR). The effects of clay fraction (0.00 37.7 wt.%) and temperature (20.0 60.3°C) were studied. The results show: (1) phenomenologically, the H2O self-diffusivity in the clay gel, D, is expressed by D/D0 = exp( 0.0198w) where D0 is the H2O self-diffusivity in bulk water of the temperature and wis the clay weight fraction (wt.%). (2) The activation energy of the diffusivity in the stevensite gel is nearly equal to that in bulk water. Thus, the normalized diffusivity, D/D0, obeys a temperature-independent master curve. (3) The exponential dependence of D/D0 on wfor w <25 wt.% (≈ 12 vol.%) can be explained by a random walk model, in which unbound H2O molecules diffuse in the geometrically tortuous pore structure of randomly scattered clay mineral grains. (4) The measured diffusivity can also be explained by a model of unbound H2O diffusing in a polymer network with a specific meshsize or characteristic interval of the crosslinkage.

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Self-Diffusion in Molten Lithium Nitrate

Zeitschrift für Naturforschung A ◽

10.1515/zna-1992-1007 ◽

1992 ◽

Vol 47 (10) ◽

pp. 1047-1050 ◽

Cited By ~ 2

Author(s):

C. Herdlicka ◽

J. Richter ◽

M. D. Zeidler

Keyword(s):

Diffusion Coefficient ◽

Diffusion Coefficients ◽

Spin Echo ◽

The Self ◽

Lithium Nitrate ◽

Equimolar Ratio ◽

Self Diffusion ◽

Field Gradients ◽

Molten Lithium ◽

Self Diffusion Coefficient

AbstractSelf-diffusion coefficients of 7Li+ ions have been measured in molten LiNO3 with several compositions of 6Li+ and 7Li+ over a temperature range from 537 to 615 K. The NMR spin-echo method with pulsed field gradients was applied. It was found that the self-diffusion coefficient depends on the isotopic composition and shows a maximum at equimolar ratio. At temperatures above 600 K this behaviour disappears.

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