Self-diffusion measurements of water adsorbed in NaY zeolites by means of NMR pulsed field gradient techniques

Kärger, Jörg; Pfeifer, H.; Riedel, E. P.; Winkler, H.

doi:10.1016/0021-9797(73)90208-7

Cited by 50 publications

(21 citation statements)

References 13 publications

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“…In some instances there can be significant consequences of enhanced mass transport when the fluid has simultaneously liquid and vapor components in sufficiently close proximity. One of the first observations of this phenomenon was reported by Karger et al 2 for water in zeolites and investigated in some detail for water in sol-gel glasses by D'Orazio et al 1 In the latter case the authors showed that enhanced diffusion results under conditions of, i) weak elastic scattering of the molecules in the vapor phase from the porous medium, and ii) fast exchange between the the vapor phase and the dense liquid or, as in our case, an adsorbed phase. 1 The latter condition ensures that all molecules are equivalent and that the effective diffusion of any molecule is given by the density weighted average of the diffusion coefficients of each separate phase.…”

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confidence: 87%

Enhanced self-diffusion of adsorbed methanol in silica aerogel

Lee

Mounce

et al. 2014

Phys. Rev. B

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Molecular transport of a two-component system of liquid and vapor in a porous medium can be anomalously increased owing to fast exchange between the two phases. 1 We have investigated this phenomenon measuring the self-diffusion coefficient of methanol adsorbed in a 98% porosity aerogel using nuclear magnetic resonance (NMR) field gradient techniques. We found enhancement of several orders of magnitude from which we determined the ballistic mean-free-path in the vapor phase. We have grown globally uniform anisotropic aerogels and applied the diffusion measurements to characterize the anisotropy. Our results are important for understanding the novel properties of superfluid 3 He confined within an aerogel framework and for application to other physical systems.

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confidence: 87%

Enhanced self-diffusion of adsorbed methanol in silica aerogel

Lee

Mounce

et al. 2014

Phys. Rev. B

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“…In the systems studied here, various diffusion domains having different diffusion coefficients may occur (e.g., diffusion of water between and within porous particles). In the case of slow exchange between the two domains, a multiexponential echo decay in the following form will be observed with each domain possessing its own diffusion coefficient D i [32,33]:…”

Section: Diffusion Domainsmentioning

confidence: 99%

Restricted diffusion in silica particles measured by pulsed field gradient NMR

Veith

Hughes

Vuataz

et al. 2004

Journal of Colloid and Interface Science

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“…Field-gradient NMR diffusometry studies of porous materials partially filled with water suggested effective self-diffusion coefficients strongly enhanced relative to the bulk liquid phase [1][2][3][4][5][6][7]. The explanation is molecular exchange between the liquid and vapor phases.…”

Section: Introductionmentioning

confidence: 92%

“…This limit was treated in the literature many times [1][2][3][4][5] and corresponds to large diffusion paths during D [12]. The amplitude of the stimulated echo is thus attenuated by diffusive displacements according to…”

Section: The Fast Liquid/vapor Exchange Limit (S L Bb D and S V Bb D)mentioning

confidence: 99%