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Hydrophobic Hydration and the Effect of NaCl Salt in the Adsorption of Hydrocarbons and Surfactants on Clathrate Hydrates
[Image: see text] Adsorption of functional molecules on the surface of hydrates is key in the understanding of hydrate inhibitors. We investigate the adsorption of a hydrocarbon chain, nonionic and ionic surfactants, and ions at the hydrate–aqueous interface. Our results suggest a strong connection...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2018
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6062839/ https://www.ncbi.nlm.nih.gov/pubmed/30062110 http://dx.doi.org/10.1021/acscentsci.8b00076 |
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author | Jiménez-Ángeles, Felipe Firoozabadi, Abbas |
author_facet | Jiménez-Ángeles, Felipe Firoozabadi, Abbas |
author_sort | Jiménez-Ángeles, Felipe |
collection | PubMed |
description | [Image: see text] Adsorption of functional molecules on the surface of hydrates is key in the understanding of hydrate inhibitors. We investigate the adsorption of a hydrocarbon chain, nonionic and ionic surfactants, and ions at the hydrate–aqueous interface. Our results suggest a strong connection between the water ordering around solutes in bulk and the affinity for the hydrates surface. We distinguish two types of water ordering around solutes: (i) hydrophobic hydration where water molecules form a hydrogen bond network similar to clathrate hydrates, and (ii) ionic hydration where water molecules align according to the polarity of an ionic group. The nonionic surfactant and the hydrocarbon chain induce hydrophobic hydration and are favorably adsorbed on the hydrate surface. Adsorption of ions and the ionic headgroups on the hydrate surface is not favorable because ionic hydration and the hydrogen bond structure of hydrates are incompatible. The nonionic surfactant is adsorbed by the headgroup and tail while adsorption of the ionic surfactants is not favorable through the head. Water ordering is analyzed using the hydrogen bond and tetrahedral density profiles as a function of the distance to the chemical groups. The adsorption of solutes is studied through the free energy profiles as a function of the distance to the hydrate surface. Salt lowers the melting temperature of hydrates, disrupts hydrophobic hydration, reduces the solubility of solutes in the aqueous solution, and increases the propensity of solutes to be adsorbed on hydrate surfaces. Our studies are performed by the unbiased and steered molecular dynamics simulations. The results are in line with experiments on the effect of salt and alkanes in hydrate antiagglomeration. |
format | Online Article Text |
id | pubmed-6062839 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-60628392018-07-30 Hydrophobic Hydration and the Effect of NaCl Salt in the Adsorption of Hydrocarbons and Surfactants on Clathrate Hydrates Jiménez-Ángeles, Felipe Firoozabadi, Abbas ACS Cent Sci [Image: see text] Adsorption of functional molecules on the surface of hydrates is key in the understanding of hydrate inhibitors. We investigate the adsorption of a hydrocarbon chain, nonionic and ionic surfactants, and ions at the hydrate–aqueous interface. Our results suggest a strong connection between the water ordering around solutes in bulk and the affinity for the hydrates surface. We distinguish two types of water ordering around solutes: (i) hydrophobic hydration where water molecules form a hydrogen bond network similar to clathrate hydrates, and (ii) ionic hydration where water molecules align according to the polarity of an ionic group. The nonionic surfactant and the hydrocarbon chain induce hydrophobic hydration and are favorably adsorbed on the hydrate surface. Adsorption of ions and the ionic headgroups on the hydrate surface is not favorable because ionic hydration and the hydrogen bond structure of hydrates are incompatible. The nonionic surfactant is adsorbed by the headgroup and tail while adsorption of the ionic surfactants is not favorable through the head. Water ordering is analyzed using the hydrogen bond and tetrahedral density profiles as a function of the distance to the chemical groups. The adsorption of solutes is studied through the free energy profiles as a function of the distance to the hydrate surface. Salt lowers the melting temperature of hydrates, disrupts hydrophobic hydration, reduces the solubility of solutes in the aqueous solution, and increases the propensity of solutes to be adsorbed on hydrate surfaces. Our studies are performed by the unbiased and steered molecular dynamics simulations. The results are in line with experiments on the effect of salt and alkanes in hydrate antiagglomeration. American Chemical Society 2018-06-21 2018-07-25 /pmc/articles/PMC6062839/ /pubmed/30062110 http://dx.doi.org/10.1021/acscentsci.8b00076 Text en Copyright © 2018 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes. |
spellingShingle | Jiménez-Ángeles, Felipe Firoozabadi, Abbas Hydrophobic Hydration and the Effect of NaCl Salt in the Adsorption of Hydrocarbons and Surfactants on Clathrate Hydrates |
title | Hydrophobic Hydration and
the Effect of NaCl Salt in the Adsorption
of Hydrocarbons and Surfactants on Clathrate Hydrates |
title_full | Hydrophobic Hydration and
the Effect of NaCl Salt in the Adsorption
of Hydrocarbons and Surfactants on Clathrate Hydrates |
title_fullStr | Hydrophobic Hydration and
the Effect of NaCl Salt in the Adsorption
of Hydrocarbons and Surfactants on Clathrate Hydrates |
title_full_unstemmed | Hydrophobic Hydration and
the Effect of NaCl Salt in the Adsorption
of Hydrocarbons and Surfactants on Clathrate Hydrates |
title_short | Hydrophobic Hydration and
the Effect of NaCl Salt in the Adsorption
of Hydrocarbons and Surfactants on Clathrate Hydrates |
title_sort | hydrophobic hydration and
the effect of nacl salt in the adsorption
of hydrocarbons and surfactants on clathrate hydrates |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6062839/ https://www.ncbi.nlm.nih.gov/pubmed/30062110 http://dx.doi.org/10.1021/acscentsci.8b00076 |
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