Behavior of the aqueous sodium chloride solutions from molecular simulations and theories

https://doi.org/10.1016/j.molliq.2022.121086Get rights and content
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Highlights

  • The Born radii of ions are practically not changed against concentration.

  • The coordination numbers of ions are practically not changed against concentration.

  • The Born equation can predict the Gibbs energy of solvation of ions satisfactorily.

  • The mean ionic activity coefficients of NaCl are predicted with a deviation of 1.1% 5. The molar conductivities of NaCl are predicted with a deviation of 1.4%

Abstract

Molecular simulations and theories are important tools for studying electrolyte solutions. In this work, molecular dynamics simulations with one of the most widely used force field combination of water and alkali and halide monovalent ion parameters were first conducted for the aqueous sodium chloride solutions to predict density, self-diffusion coefficients and molar conductivity. Then the radial distribution functions were analyzed to obtain the first shell solvation radii and coordination numbers of ions, which were found practically unchanged against concentration. Together with the force field parameters, they were further applied into various molecular theories to predict the Gibbs energy of solvation, static relative permittivity, mean ionic activity coefficients and molar conductivity. It is remarkable to see that the mean ionic activity coefficients and molar conductivity can be predicted with deviations of 1.1 % and 1.4 %, respectively, up to 6 mol/kg H2O.

Keywords

MD simulations
Molecular theories
Self-diffusion
Molar conductivity
Static relative permittivity

Data availability

Data will be made available on request.

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