Le, T;
Striolo, A;
Cole, DR;
(2015)
CO2-C4H10 Mixtures Simulated in Silica Slit Pores: Relation between Structure and Dynamics.
Journal of Physical Chemistry C
, 119
(27)
pp. 15274-15284.
10.1021/acs.jpcc.5b03160.
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Abstract
Equilibrium molecular dynamics simulations were conducted for pure n-butane and for mixtures containing n-butane and carbon dioxide confined in 2 nm wide slit-shaped pores carved out of cristobalite silica. A range of thermodynamic conditions was explored, including temperatures ranging from subcritical to supercritical, and various densities. Preferential adsorption of carbon dioxide near the -OH groups on the surface was observed, where the adsorbed CO<inf>2</inf> molecules tend to interact simultaneously with more than one -OH group. Analysis of the simulation results suggests that the preferential CO<inf>2</inf> adsorption to the pore walls weakens the adsorption of n-butane, lowers the activation energy for n-butane diffusivity, and consequently enhances n-butane mobility. The diffusion results obtained for pure CO<inf>2</inf> are consistent with strong adsorption on the pore walls, as the CO<inf>2</inf> self-diffusion coefficient is low at low densities, increases with loading, and exhibits a maximum as the density is increased further because of hindrance effects. As the temperature increases, the maximum in self-diffusion coefficient is narrower, steeper, and shifted to lower loading. The simulation results are also quantified in terms of molecular density profiles for both butane and CO<inf>2</inf> and in terms of residence time of the various molecules near the solid substrate. Our results could be useful for designing separation devices and also for better understanding the behavior of fluids in subsurface environments.
| Type: | Article |
|---|---|
| Title: | CO2-C4H10 Mixtures Simulated in Silica Slit Pores: Relation between Structure and Dynamics |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1021/acs.jpcc.5b03160 |
| Publisher version: | http://dx.doi.org/10.1021/acs.jpcc.5b03160 |
| Additional information: | Copyright © 2015 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in J. Phys. Chem. C, copyright © American Chemical Society after peer review and technical editing by the publisher.To access the final edited and published work see: http://dx.doi.org/10.1021/acs.jpcc.5b03160 |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1470545 |
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