A Thermodynamic Model for the Solubility of SO<sub>2</sub> in Multi-Ion Electrolyte Solutions and Its Applications

A solubility model of SO<sub>2</sub> in multi-ion electrolyte solutions has been developed by the activity-fugacity relation at vapor-liquid equilibria. The fugacity coefficient of SO<sub>2</sub> in the vapor phase is calculated by the equation of state (EOS) of pure SO<su...

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Main Authors: Baoyi Feng, Zequn Zhang, Mei Xu, Shide Mao
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/7/3927
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author Baoyi Feng
Zequn Zhang
Mei Xu
Shide Mao
author_facet Baoyi Feng
Zequn Zhang
Mei Xu
Shide Mao
author_sort Baoyi Feng
collection DOAJ
description A solubility model of SO<sub>2</sub> in multi-ion electrolyte solutions has been developed by the activity-fugacity relation at vapor-liquid equilibria. The fugacity coefficient of SO<sub>2</sub> in the vapor phase is calculated by the equation of state (EOS) of pure SO<sub>2</sub>, and the activity coefficient of SO<sub>2</sub> in the liquid phase is calculated by the Pitzer activity coefficient theory. The model can reproduce the reliable solubility data of SO<sub>2</sub> in pure water and multi-ion electrolyte solutions (Na<sup>+</sup>, K<sup>+</sup>, Cl<sup>−</sup>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>SO</mi></mrow><mn>4</mn><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></mrow></semantics></math></inline-formula>) within or close to experimental uncertainties. Although the second-order and third-order interaction parameters between SO<sub>2</sub> and Mg<sup>2+</sup> and Ca<sup>2+</sup> have been adopted by an approximation, the solubility model can also be extended to predict the SO<sub>2</sub> solubility in seawater. In addition, combining with the EOS of a CO<sub>2</sub>-SO<sub>2</sub> fluid mixture, the model can be used to predict the solubility of a CO<sub>2</sub>-SO<sub>2</sub> mixture in aqueous electrolyte solutions. The calculated results are consistent with experimental data, which indicates that the solubility model has certain predictive ability.
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spelling doaj-art-2cebe52d2e3b43df8bc36a42f0a5f6452025-08-20T02:17:00ZengMDPI AGApplied Sciences2076-34172025-04-01157392710.3390/app15073927A Thermodynamic Model for the Solubility of SO<sub>2</sub> in Multi-Ion Electrolyte Solutions and Its ApplicationsBaoyi Feng0Zequn Zhang1Mei Xu2Shide Mao3School of Earth Sciences and Resources, China University of Geoscience, Beijing 100083, ChinaSchool of Earth Sciences and Resources, China University of Geoscience, Beijing 100083, ChinaSchool of Earth Sciences and Resources, China University of Geoscience, Beijing 100083, ChinaSchool of Earth Sciences and Resources, China University of Geoscience, Beijing 100083, ChinaA solubility model of SO<sub>2</sub> in multi-ion electrolyte solutions has been developed by the activity-fugacity relation at vapor-liquid equilibria. The fugacity coefficient of SO<sub>2</sub> in the vapor phase is calculated by the equation of state (EOS) of pure SO<sub>2</sub>, and the activity coefficient of SO<sub>2</sub> in the liquid phase is calculated by the Pitzer activity coefficient theory. The model can reproduce the reliable solubility data of SO<sub>2</sub> in pure water and multi-ion electrolyte solutions (Na<sup>+</sup>, K<sup>+</sup>, Cl<sup>−</sup>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mi>SO</mi></mrow><mn>4</mn><mrow><mn>2</mn><mo>−</mo></mrow></msubsup></mrow></semantics></math></inline-formula>) within or close to experimental uncertainties. Although the second-order and third-order interaction parameters between SO<sub>2</sub> and Mg<sup>2+</sup> and Ca<sup>2+</sup> have been adopted by an approximation, the solubility model can also be extended to predict the SO<sub>2</sub> solubility in seawater. In addition, combining with the EOS of a CO<sub>2</sub>-SO<sub>2</sub> fluid mixture, the model can be used to predict the solubility of a CO<sub>2</sub>-SO<sub>2</sub> mixture in aqueous electrolyte solutions. The calculated results are consistent with experimental data, which indicates that the solubility model has certain predictive ability.https://www.mdpi.com/2076-3417/15/7/3927SO<sub>2</sub>solubility modelelectrolyte solutionsequation of state
spellingShingle Baoyi Feng
Zequn Zhang
Mei Xu
Shide Mao
A Thermodynamic Model for the Solubility of SO<sub>2</sub> in Multi-Ion Electrolyte Solutions and Its Applications
Applied Sciences
SO<sub>2</sub>
solubility model
electrolyte solutions
equation of state
title A Thermodynamic Model for the Solubility of SO<sub>2</sub> in Multi-Ion Electrolyte Solutions and Its Applications
title_full A Thermodynamic Model for the Solubility of SO<sub>2</sub> in Multi-Ion Electrolyte Solutions and Its Applications
title_fullStr A Thermodynamic Model for the Solubility of SO<sub>2</sub> in Multi-Ion Electrolyte Solutions and Its Applications
title_full_unstemmed A Thermodynamic Model for the Solubility of SO<sub>2</sub> in Multi-Ion Electrolyte Solutions and Its Applications
title_short A Thermodynamic Model for the Solubility of SO<sub>2</sub> in Multi-Ion Electrolyte Solutions and Its Applications
title_sort thermodynamic model for the solubility of so sub 2 sub in multi ion electrolyte solutions and its applications
topic SO<sub>2</sub>
solubility model
electrolyte solutions
equation of state
url https://www.mdpi.com/2076-3417/15/7/3927
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