Effects of disordered porous media on the vapour-liquid phase equilibrium in ionic fluids: application of the association concept

Holovko, M.; Patsahan, T.; Patsahan, Oksana

doi:10.1016/j.molliq.2016.10.045

Cited by 19 publications

(19 citation statements)

References 75 publications

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“…The solid line corresponds to the coexistence curve in the bulk. Consistent with earlier theoretical investigations, 32,47 confinement narrows the phase coexistence envelope. While the dilute branch is weakly dependent on the slit pore width, the concentrated branch considerably shifts leftwards as the pore width decreases.…”

Section: A Phase Diagram Of Confined Ionic Fluidssupporting

confidence: 89%

Does capillary evaporation limit the accessibility of nonaqueous electrolytes to the ultrasmall pores of carbon electrodes?

Liu

Zhang

2018

The Journal of Chemical Physics

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Porous carbons have been widely utilized as electrode materials for capacitive energy storage. Whereas the importance of pore size and geometry on the device performance has been well recognized, little guidance is available for identification of carbon materials with ideal porous structures. In this work, we study the phase behavior of ionic fluids in slit pores using the classical density functional theory. Within the framework of the restricted primitive model for nonaqueous electrolytes, we demonstrate that the accessibility of micropores depends not only on the ionic diameters (or desolvation) but also on their wetting behavior intrinsically related to the vapor-liquid or liquid-liquid phase separation of the bulk ionic systems. Narrowing the pore size from several tens of nanometers to subnanometers may lead to a drastic reduction in the capacitance due to capillary evaporation. The wettability of micropores deteriorates as the pore size is reduced but can be noticeably improved by raising the surface electrical potential. The theoretical results provide fresh insights into the properties of confined ionic systems beyond electric double layer models commonly employed for rational design/selection of electrolytes and electrode materials.

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Section: A Phase Diagram Of Confined Ionic Fluidssupporting

confidence: 89%

Does capillary evaporation limit the accessibility of nonaqueous electrolytes to the ultrasmall pores of carbon electrodes?

Liu

Zhang

2018

The Journal of Chemical Physics

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“…The developed SPT2 approach was generalized for fluids of anisotropic particles [20,21], for a hard sphere mixture [22] and for a mixture of hard sphere and anisotropic particles [23,24] in disordered porous media. The obtained results for the models considered were also used as the reference system taking into account attractive [24,25], associative [26] and Coulombic [27][28][29] interactions.…”

Section: Introductionmentioning

confidence: 99%

Diffusion of hard sphere fluids in disordered porous media: Enskog theory description

Holovko¹,

Korvatska²

2020

Condens. Matter Phys.

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We use the Enskog theory for the description of the self-diffusion coefficient of hard sphere fluids in disordered porous media. Using the scaled particle theory previously developed by us for the description of thermodynamic properties of hard sphere fluids, simple analytical expressions for the contact values of the fluid-fluid and fluidmatrix pair distribution functions are obtained and used as the input of Enskog theory. The expressions obtained for the contact values are described only by the geometric porosity and do not include the dependence on other types of porosity that are important for the description of thermodynamic properties. It is shown that the application of such contact values neglects the effects of trapping of fluid particles by a matrix and at least the probe particle porosity φ should be included in the Enskog theory for a correct description of the matrix influence. In this paper we extend the Enskog theory by changing the contact values of the fluid-matrix and the fluid-fluid pair distribution functions with new properties which include the dependence not only on geometric porosity but also on probe particle porosity φ. It is shown that such semi-empirical improvement of the Enskog theory corresponds to SPT2b1 approximation for the description of thermodynamic properties and it predicts correct trends for the influence of porous media on the diffusion coefficient of a hard sphere fluid in disordered porous media. Good agreement with computer simulations is illustrated. The effects of fluid density, fluid to matrix sphere size ratio, matrix porosity and matrix morphology on the self-diffusion coefficient of hard sphere fluids are discussed.

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“…where the quantities with a "tilde" are Fourier transforms of perturbative parts of the corresponding interaction potentials [see (12)] and E (O) are even (odd) numbers. ρ k indicates a column vector of elements ρ k,0 , ρ 1 k,+ , .…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Vapour-liquid critical parameters of a 2:1 primitive model of ionic fluids confined in disordered porous media

Patsahan

Holovko

2018

Journal of Molecular Liquids

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We study the vapour-liquid critical parameters of an ionic fluid confined in a disordered porous medium by using the theory which combines the collective variables approach with an extension of the scaled particle theory. The ionic fluid is described as a two-component charge-and sizeasymmetric primitive model, and a porous medium is modelled as a disordered matrix formed by hard-spheres obstacles. In the particular case of the fixed valencies 2:1, the coexistence curves and the corresponding critical parameters are calculated for different matrix porosities as well as for different diameters of matrix and fluid particles. The obtained results show that the general trends of the reduced critical temperature and the reduced critical density with the microscopic characteristics are similar to the trends obtained in the monovalent case. At the same time, it is noticed that an ion charge asymmetry significantly weakens the effect of the matrix presence.

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Effects of disordered porous media on the vapour-liquid phase equilibrium in ionic fluids: application of the association concept

Cited by 19 publications

References 75 publications

Does capillary evaporation limit the accessibility of nonaqueous electrolytes to the ultrasmall pores of carbon electrodes?

Does capillary evaporation limit the accessibility of nonaqueous electrolytes to the ultrasmall pores of carbon electrodes?

Diffusion of hard sphere fluids in disordered porous media: Enskog theory description

Vapour-liquid critical parameters of a 2:1 primitive model of ionic fluids confined in disordered porous media

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