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Molecular Dynamics Simulations of Diffusion in Mesoporous Glass

Fernandes, Neil E. and Gavalas, George R. (1999) Molecular Dynamics Simulations of Diffusion in Mesoporous Glass. Industrial & Engineering Chemistry Research, 38 (3). pp. 723-730. ISSN 0888-5885. https://resolver.caltech.edu/CaltechAUTHORS:20151007-090423856

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Abstract

The effect of gas−solid intrapore potential and surface roughness on diffusion in a single capillary was investigated by molecular dynamics simulations. Calculations were carried out for nitrogen and isobutane under free molecular flow conditions in pores of diameter 4−14 Å at temperatures of 200−800 K. The gases were treated as Lennard-Jones atoms and the pore surface was taken as cylindrical, exerting a 9−3 potential. No energy transfer was considered between the gas and solid, but interaction with the roughened pore wall provided the scattering required for diffusive transport. Two effects of the gas−solid potential were examined in some detail. One is the enhanced intrapore gas concentration which increases the flux, and the other is the bending of the molecular trajectories which decreases the flux. In pores of radius 20 Å, both effects were significant for temperatures as high as 500 K and were enhanced as the temperature decreased. For nitrogen, the two effects partially canceled each other over the temperature range examined, resulting in a temperature dependence similar to that of Knudsen diffusion. For isobutane, the partitioning effect dominated the path curvature effect at temperatures as high as 500 K.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/ie9801150DOIArticle
http://pubs.acs.org/doi/abs/10.1021/ie9801150PublisherArticle
ORCID:
AuthorORCID
Gavalas, George R.0000-0003-1468-6835
Additional Information:© 1999 American Chemical Society. Received for review February 18, 1998. Revised manuscript received September 4, 1998. Accepted October 19, 1998. This research was supported by DOE University Coal Research Program (Grant DE-FG22-92PC92525).
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG22-92PC92525
Issue or Number:3
Record Number:CaltechAUTHORS:20151007-090423856
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20151007-090423856
Official Citation:Molecular Dynamics Simulations of Diffusion in Mesoporous Glass Neil E. Fernandes and George R. Gavalas Industrial & Engineering Chemistry Research 1999 38 (3), 723-730 DOI: 10.1021/ie9801150
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:60838
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:13 Oct 2015 15:03
Last Modified:03 Oct 2019 09:01

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