Systematic evaluation of parameterization approaches for the ePPC-SAFT model for aqueous alkali halide solutions. II. Alkali bromides, iodides, fluorides, and lithium halides

Duan, Yuan-Yuan; Kontogeorgis, Georgios M.; Hemptinne, Jean-Charles de

doi:10.1016/j.fluid.2023.113853

Cited by 4 publications

(20 citation statements)

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“…for MIAC) and maximum absolute percentage deviations (MADs) for MIAC, VLE, and density of ePPC-SAFT with IP-Wertheim for aqueous alkali halide solutions and with IP-Bjerrum for the four aqueous alkali chloride (NaCl, KCl, RbCl, and CsCl) solutions for comparison. Compared to previous works, 18,19 in which the association sites were not labeled, the overall accuracy is approximately the same for MIAC and is slightly better for The hard sphere diameters are calculated using σ HS = r HS σ Pauling , where r HS is regressed. d The parameters are set constant to the value of water.…”

Section: Aqueous Alkali Halide Solutionsmentioning

confidence: 80%

“…In the ePPC-SAFT model, − ,− the residual Helmholtz free energy is given as A res = A hc + A disp + A assoc + A polar + A NAHS + A MSA + A Born where the superscript hc denotes hard-chain, disp denotes dispersion, assoc denotes association, polar denotes multipolar as presented by refs − , NAHS denotes the nonadditive hard sphere as presented by ref . The NAHS term corrects for the combining rule of the diameters and is used in this work only for water–methanol, for which the parameter was obtained in previous work .…”

Section: Methodsmentioning

confidence: 99%

“…For ions, in previous works, − the ion association scheme was identified only by the number of sites: all cations were considered as proton donors (positive charge) and all anions were considered as proton acceptors (negative charge). The cation sites could interact with both the proton acceptor sites of the solvent as well as with any of the anion sites, and vice versa.…”

Section: Methodsmentioning

confidence: 99%

“…It has also been used for supplementing the Born term for the solvation effect, as suggested by Wu and Prausnitz, for introducing “additional association interactions between ions and solvent (water) molecules to represent interactions between charged ions and water”. In previous works, − Wertheim’s theory is used for the solvent–solvent, ion–solvent, and ion–ion associations. In our new association framework, it is used for the solvent–solvent and ion–solvent associations and is compared for the ion–ion association with Bjerrum’s theory, which will be introduced in Sections 2.1.2 and 2.1.3.…”

Section: Methodsmentioning

confidence: 99%

“…In early electrolyte SAFT models, − ,, short-range ion–ion and ion–solvent interactions are usually accounted for using the dispersion interactions only. However, in recent works, ion association has been taken into account, − either in the association term or in the electrostatic term. In ref , a dissociation factor was introduced into the DH term in the ePC-SAFT model.…”

Section: Introductionmentioning

confidence: 99%

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Ion Pairing in ePPC-SAFT for Aqueous and Mixed-Solvent Alkali Halide Solutions

Yang,

Raeispour Shirazi,

Roa Pinto

et al. 2024

Ind. Eng. Chem. Res.

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Short-range ion−solvent and ion−ion interactions need to be taken into account in molecule-based electrolyte equations of state. The ePPC-SAFT (electrolyte polar perturbed chain statistical associating fluid theory) model consists of hard chain, dispersion, association, multipolar, nonadditive hard sphere, mean spherical approximation, and Born contributions. Using Wertheim's first-order thermodynamic perturbation theory for associating fluids to account for short-range cation−anion interactions offers significant advantages over models that use ion−ion dispersion interactions only. However, the ionic association framework assigns the same number of sites for ion−solvent and cation−anion interactions, assuming the formation of ion clusters. This work proposes a new association framework in which ion−ion and ion−solvent association sites are labeled, restricting the ion−ion association site number to one per ion to prevent the formation of larger ion clusters. This approach improves modeling accuracy compared to the original model, in which ion clustering was considered, without increasing the number of adjustable parameters. Furthermore, this work proposes a generalized Bjerrum theory with one adjustable parameter in the association strength function, as in Wertheim's theory, and proposes an analytical approximation for the Bjerrum integral to speed up calculations. This work uses Wertheim's theory for short-range ion−solvent interactions and compares Wertheim's theory and Bjerrum's theory for short-range ion−ion interactions, i.e., ion pairing. The new association framework with Wertheim's theory for both short-range ion−ion and ion−solvent associations is demonstrated to be significantly more accurate compared to Bjerrum's theory and slightly more accurate than the previous best practice. The model extends to mixed-solvent electrolyte solutions. Furthermore, the contributions of Helmholtz free energy terms and number of bonds of the ions are analyzed.

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Section: Aqueous Alkali Halide Solutionsmentioning

confidence: 80%