Adsorption of water, methanol, and their mixtures in slit graphite pores

The behavior of water, methanol, and water-methanol mixtures confined in narrow slit graphite pores as a function of pore size was investigated by Monte Carlo, hybrid Monte Carlo, and Molecular Dynamics simulations. Interactions were described using TIP4P/2005 for water, OPLS/2016 for methanol, and...

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Autores: Pršlja, P., Lomba, Enrique, Gómez-Álvarez, Paula, Urbič, Tomaz, Noya, Eva G.
Tipo de recurso: artículo
Estado:Versión enviada para evaluación y publicación
Fecha de publicación:2019
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/180094
Acceso en línea:http://hdl.handle.net/10261/180094
Access Level:acceso abierto
Palabra clave:TIP4P Monte Carlo methods Adsorption Chemical elements Carbon based materials Gas phase Hydrogen bonding Molecular dynamics Mass diffusion, Thermodynamic states and processes
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spelling Adsorption of water, methanol, and their mixtures in slit graphite poresPršlja, P.Lomba, EnriqueGómez-Álvarez, PaulaUrbič, TomazNoya, Eva G.TIP4P Monte Carlo methods Adsorption Chemical elements Carbon based materials Gas phase Hydrogen bonding Molecular dynamics Mass diffusion, Thermodynamic states and processesThe behavior of water, methanol, and water-methanol mixtures confined in narrow slit graphite pores as a function of pore size was investigated by Monte Carlo, hybrid Monte Carlo, and Molecular Dynamics simulations. Interactions were described using TIP4P/2005 for water, OPLS/2016 for methanol, and cross interactions fitted to excess water/methanol properties over the whole range of concentrations, which provide a rather accurate description of water-methanol mixtures. As expected for hydrophobic pores, whereas pure methanol is adsorbed already from the gas phase, pure water only enters the pore at pressures well beyond bulk saturation for all pore sizes considered. When adsorbed from a mixture, however, water adsorbs at much lower pressures due to the formation of hydrogen bonds with previously adsorbed methanol molecules. For all studied compositions and pore sizes, methanol adsorbs preferentially over water at liquid-vapor equilibrium conditions. In pure components, both water and methanol are microscopically structured in layers, the number of layers increasing with pore size. This is also the case in adsorbed mixtures, in which methanol has a higher affinity for the walls. This becomes more evident as the pore widens. Diffusion of pure water is higher than that of pure methanol for all pore sizes due to the larger size of the methyl group. In mixtures, both components present similar diffusivities at all pore sizes, which is explained in terms of the coupling of molecular movements due to strong hydrogen bonding between methanol and water molecules. This is particularly evident in very narrow pores, in which pure methanol diffusion is completely impeded on the time scale of our simulations, but the presence of a small amount of water molecules facilitates alcohol diffusion following a single-file mechanism. Additionally, our results indicate that pure water diffusivities display a non-monotonous dependence of pore size, due to effects of confinement (proximity to a fluid-solid-fluid transition induced by confinement as reported in previous work) and the dynamic anomalies of water.Peer ReviewedAmerican Institute of PhysicsEuropean CommissionConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2019201920192019info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Preprintinfo:eu-repo/semantics/submittedVersionhttp://hdl.handle.net/10261/180094reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/EC/H2020/734276info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/FIS2017-89361-C3-2-PSíinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/1800942026-05-22T06:33:51Z
dc.title.none.fl_str_mv Adsorption of water, methanol, and their mixtures in slit graphite pores
title Adsorption of water, methanol, and their mixtures in slit graphite pores
spellingShingle Adsorption of water, methanol, and their mixtures in slit graphite pores
Pršlja, P.
TIP4P Monte Carlo methods Adsorption Chemical elements Carbon based materials Gas phase Hydrogen bonding Molecular dynamics Mass diffusion, Thermodynamic states and processes
title_short Adsorption of water, methanol, and their mixtures in slit graphite pores
title_full Adsorption of water, methanol, and their mixtures in slit graphite pores
title_fullStr Adsorption of water, methanol, and their mixtures in slit graphite pores
title_full_unstemmed Adsorption of water, methanol, and their mixtures in slit graphite pores
title_sort Adsorption of water, methanol, and their mixtures in slit graphite pores
dc.creator.none.fl_str_mv Pršlja, P.
Lomba, Enrique
Gómez-Álvarez, Paula
Urbič, Tomaz
Noya, Eva G.
author Pršlja, P.
author_facet Pršlja, P.
Lomba, Enrique
Gómez-Álvarez, Paula
Urbič, Tomaz
Noya, Eva G.
author_role author
author2 Lomba, Enrique
Gómez-Álvarez, Paula
Urbič, Tomaz
Noya, Eva G.
author2_role author
author
author
author
dc.contributor.none.fl_str_mv European Commission
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv TIP4P Monte Carlo methods Adsorption Chemical elements Carbon based materials Gas phase Hydrogen bonding Molecular dynamics Mass diffusion, Thermodynamic states and processes
topic TIP4P Monte Carlo methods Adsorption Chemical elements Carbon based materials Gas phase Hydrogen bonding Molecular dynamics Mass diffusion, Thermodynamic states and processes
description The behavior of water, methanol, and water-methanol mixtures confined in narrow slit graphite pores as a function of pore size was investigated by Monte Carlo, hybrid Monte Carlo, and Molecular Dynamics simulations. Interactions were described using TIP4P/2005 for water, OPLS/2016 for methanol, and cross interactions fitted to excess water/methanol properties over the whole range of concentrations, which provide a rather accurate description of water-methanol mixtures. As expected for hydrophobic pores, whereas pure methanol is adsorbed already from the gas phase, pure water only enters the pore at pressures well beyond bulk saturation for all pore sizes considered. When adsorbed from a mixture, however, water adsorbs at much lower pressures due to the formation of hydrogen bonds with previously adsorbed methanol molecules. For all studied compositions and pore sizes, methanol adsorbs preferentially over water at liquid-vapor equilibrium conditions. In pure components, both water and methanol are microscopically structured in layers, the number of layers increasing with pore size. This is also the case in adsorbed mixtures, in which methanol has a higher affinity for the walls. This becomes more evident as the pore widens. Diffusion of pure water is higher than that of pure methanol for all pore sizes due to the larger size of the methyl group. In mixtures, both components present similar diffusivities at all pore sizes, which is explained in terms of the coupling of molecular movements due to strong hydrogen bonding between methanol and water molecules. This is particularly evident in very narrow pores, in which pure methanol diffusion is completely impeded on the time scale of our simulations, but the presence of a small amount of water molecules facilitates alcohol diffusion following a single-file mechanism. Additionally, our results indicate that pure water diffusivities display a non-monotonous dependence of pore size, due to effects of confinement (proximity to a fluid-solid-fluid transition induced by confinement as reported in previous work) and the dynamic anomalies of water.
publishDate 2019
dc.date.none.fl_str_mv 2019
2019
2019
2019
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Preprint
info:eu-repo/semantics/submittedVersion
format article
status_str submittedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/180094
url http://hdl.handle.net/10261/180094
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
#PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/EC/H2020/734276
info:eu-repo/grantAgreement/AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020/FIS2017-89361-C3-2-P
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv American Institute of Physics
publisher.none.fl_str_mv American Institute of Physics
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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