Adsorption and diffusion of methane in silica nanopores: A comparison of single-site and five-site models

Bhatia, S.K. and Nicholson, D. (2012) Adsorption and diffusion of methane in silica nanopores: A comparison of single-site and five-site models. Journal of Physical Chemistry C, 116 3: 2344-2355.


Author Bhatia, S.K.
Nicholson, D.
Title Adsorption and diffusion of methane in silica nanopores: A comparison of single-site and five-site models
Journal name Journal of Physical Chemistry C   Check publisher's open access policy
ISSN 1932-7447
1932-7455
Publication date 2012-01
Year available 2011
Sub-type Article (original research)
DOI 10.1021/jp210593d
Volume 116
Issue 3
Start page 2344
End page 2355
Total pages 12
Place of publication Washington, DC, United States
Publisher American Chemical Society
Collection year 2012
Language eng
Abstract We report a comparison of the adsorption and transport characteristics of one-site and five-site molecular models of methane in silica nanopores, using grand canonical Monte Carlo and equilibrium molecular dynamics simulations. It is found that while the two models show similar effective molecular sizes, based on similar high-pressure densities in the bulk and nanopore fluids, the conventional parameters of the one-site model yield somewhat stronger intermolecular and pore wall interaction. This leads to higher densities in the bulk and adsorbed fluids at intermediate pressures, for the one-site model. However, the self- and collective-diffusion coefficients are similar for the two models for most nanopores, except at low densities in large mesopores. In this case, the five-site model shows slightly larger low-density diffusivity, due to its weaker interaction with the pore surface. On the basis of comparison with molecular dynamics simulations for the five-site model fluid, the predictive ability of our recent frictional theory of transport in nanopores is confirmed over a wide range of densities and pore diameters, using only the low-density diffusivity from a single simulation. Exceptions are found in the region of the critical point where the correlation length of the fluid diverges and when intermolecular interactions become significant in narrow nanopores where the fluid is nearly one-dimensional. In such cases, the local average density model used to estimate local transport properties becomes inaccurate.
Keyword Molecular-Dynamics Simulations
Carbon Nanotubes
Transport-Properties
Fluids
Alpo4-5
Flow
Equilibrium
Micropores
Membranes
Mixtures
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Publication Date (Web): 21 December 2011.

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
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