Inhibitory effect of adsorbed water on the transport of methane in carbon nanotubes

Liu, Lang, Hu, Chunxia, Nicholson, David and Bhatia, Suresh K. (2017) Inhibitory effect of adsorbed water on the transport of methane in carbon nanotubes. Langmuir, 33 25: 6280-6291. doi:10.1021/acs.langmuir.7b01070


Author Liu, Lang
Hu, Chunxia
Nicholson, David
Bhatia, Suresh K.
Title Inhibitory effect of adsorbed water on the transport of methane in carbon nanotubes
Journal name Langmuir   Check publisher's open access policy
ISSN 1520-5827
0743-7463
Publication date 2017-06-27
Year available 2017
Sub-type Article (original research)
DOI 10.1021/acs.langmuir.7b01070
Open Access Status Not yet assessed
Volume 33
Issue 25
Start page 6280
End page 6291
Total pages 12
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Subject 2500 Materials Science
3104 Condensed Matter Physics
3110 Surfaces and Interfaces
1607 Spectroscopy
1603 Electrochemistry
Abstract We investigate the transport diffusion of methane at 300 K and pressures of up to 15 bar in dry and wetted carbon nanotubes (CNTs) having diameters ranging from 0.95 to 2.034 nm using nonequilibrium molecular dynamics (NEMD) simulation. Because of their strong hydrogen bonding, preadsorbed water molecules transport in the form of clusters and block the diffusion of methane, reducing the Onsager coefficient of methane dramatically compared to that in dry CNTs. The reduction in the methane Onsager coefficient is greater in narrower CNTs or at higher water densities. Because the diameter of the water clusters is almost invariant with water density, the Onsager coefficient of water in the (10, 10) CNT increases linearly with water density. It is further found that whereas decreasing the CNT diameter from 2.034 to 0.95 nm enhances the Onsager coefficient of pure methane by about 1 order of magnitude, the Onsager coefficient of water is almost independent of the CNT diameter at a water density of 0.05 g/cm. We propose a theoretical model for the strong dependency of methane diffusion in wetted CNTs on the Onsager coefficient of water, the preadsorbed water density, and the CNT diameter. The model predicts the Onsager coefficients of the methane/water mixture from the Onsager coefficients of the pure components. Our study provides a basic understanding of the coupled diffusion of immiscible components in nanochannels and will facilitate progress in gas storage and carbon capture as well as nanofiltration and biomedical and biotechnological applications.
Formatted abstract
We investigate the transport diffusion of methane at 300 K and pressures of up to 15 bar in dry and wetted carbon nanotubes (CNTs) having diameters ranging from 0.95 to 2.034 nm using nonequilibrium molecular dynamics (NEMD) simulation. Because of their strong hydrogen bonding, preadsorbed water molecules transport in the form of clusters and block the diffusion of methane, reducing the Onsager coefficient of methane dramatically compared to that in dry CNTs. The reduction in the methane Onsager coefficient is greater in narrower CNTs or at higher water densities. Because the diameter of the water clusters is almost invariant with water density, the Onsager coefficient of water in the (10, 10) CNT increases linearly with water density. It is further found that whereas decreasing the CNT diameter from 2.034 to 0.95 nm enhances the Onsager coefficient of pure methane by about 1 order of magnitude, the Onsager coefficient of water is almost independent of the CNT diameter at a water density of 0.05 g/cm3. We propose a theoretical model for the strong dependency of methane diffusion in wetted CNTs on the Onsager coefficient of water, the preadsorbed water density, and the CNT diameter. The model predicts the Onsager coefficients of the methane/water mixture from the Onsager coefficients of the pure components. Our study provides a basic understanding of the coupled diffusion of immiscible components in nanochannels and will facilitate progress in gas storage and carbon capture as well as nanofiltration and biomedical and biotechnological applications.
Keyword Chemistry, Multidisciplinary
Chemistry, Physical
Materials Science, Multidisciplinary
Chemistry
Materials Science
Q-Index Code C1
Q-Index Status Provisional Code
Grant ID DP150101824
Institutional Status UQ

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