Scaled charges at work: Salting out and interfacial tension of methane with electrolyte solutions from computer simulations

Blazquez, S. and Zeron, I.M. and Martin Conde, Maria and Abascal, J.L.F. and Vega, C. (2020). Scaled charges at work: Salting out and interfacial tension of methane with electrolyte solutions from computer simulations. "Fluid Phase Equilibria", v. 513 ; p. 112548. ISSN 03783812. https://doi.org/10.1016/j.fluid.2020.112548.

Description

Title: Scaled charges at work: Salting out and interfacial tension of methane with electrolyte solutions from computer simulations
Author/s:
  • Blazquez, S.
  • Zeron, I.M.
  • Martin Conde, Maria
  • Abascal, J.L.F.
  • Vega, C.
Item Type: Article
Título de Revista/Publicación: Fluid Phase Equilibria
Date: 5 March 2020
ISSN: 03783812
Volume: 513
Subjects:
Faculty: E.T.S.I. Industriales (UPM)
Department: Ingeniería Química Industrial y del Medio Ambiente
Creative Commons Licenses: None

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Abstract

The solubility of methane in water decreases when a small amount of salt is present. This is usually denoted as the salting out effect (i.e., the methane is expelled from the solution when it contains small amounts of salt). The effect is important, for instance the solubility is reduced by a factor of three in a 4 m (mol/kg) NaCl solution. Some years ago we showed that the salting out effect of methane in water can be described qualitatively by molecular models using computer simulations. However the salting out effect was overestimated. In fact, it was found that the solubility of methane was reduced by a factor of eight. This points to limitations in the force field used. In this work we have carried out direct coexistence simulations to describe the salting out effect of methane in water using a recently proposed force field (denoted as Madrid-2019) based on the use of scaled charges for the ions and the TIP4P/2005 force field for water. For NaCl the results of the Madrid-2019 force field significantly improve the description of salting out of methane. For other salts the results are quite reasonable. Thus the reduction of the charge of the ions also seems to be able to improve the description of salting out effect of methane in water. Besides this we shall show that the brine methane interface exhibits an increased interfacial tension as compared to that of the water-methane system. It is well known that electrolytes tend to increase the surface tension of liquid water, and this seems also to be the case for the interface between water and methane.

Funding Projects

TypeCodeAcronymLeaderTitle
Madrid Regional GovernmentAPOYO-JOVENES-01HQ1S-129- B5E4MMCavItieSMaria Martin CondeCaptura selectiva de moléculas de interés industrial en compuestos clatrato mediante simulación computacional
Government of SpainFIS2016-78117-PUnspecifiedUnspecifiedMODELADO DE LA CRISTALIZACION EN DISOLUCION

More information

Item ID: 64965
DC Identifier: http://oa.upm.es/64965/
OAI Identifier: oai:oa.upm.es:64965
DOI: 10.1016/j.fluid.2020.112548
Official URL: https://doi.org/10.1016/j.fluid.2020.112548
Deposited by: María Martin Conde
Deposited on: 26 Oct 2020 07:51
Last Modified: 26 Oct 2020 07:51
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