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Context <p>Understanding the behavior of potassium carbonate (K<sub>2</sub>CO<sub>3</sub>) in water is essential for improving its performance in various chemical and industrial applications. The physicochemical properties of K<sub>2</sub>CO<sub>3</sub> aqueous solutions determine its reactivity, stability, and efficiency in processes such as CO2 capture and alkaline electrochemistry. In this study, we combined molecular dynamics simulations and spectroscopic experiments to elucidate the microstructural, dynamic, and dielectric behaviors of the {K<sub>2</sub>CO<sub>3</sub>–H<sub>2</sub>O} system across concentrations ranging from 0.11 to 1.07&#xa0;mol.kg<sup>−1</sup> at T = 298.15&#xa0;K. The analyses reveal strong ion-water correlations, coordination changes within hydration shells, and concentration-dependent variations in ionic mobility and dielectric constant. Experimental FTIR and NMR measurements validated the simulated structures and provided deeper insights into the hydration mechanisms and ion–water interactions governing the dissolution and transport properties of K<sub>2</sub>CO<sub>3</sub> in water.</p> Methods <p>Classical molecular dynamics simulations were performed using GROMACS 2020.6 with the CHARMM36 force field for ions and the SPC/E water model. Ionic interactions were modeled through long-range Coulombic and short-range Lennard–Jones potentials. Systems spanning 0.11–1.07&#xa0;mol.kg<sup>−1</sup> were equilibrated for 100&#xa0;ns in both NVT and NPT ensembles, followed by 100&#xa0;ns production runs at 298&#xa0;K and 1&#xa0;bar using the PME algorithm for electrostatics. FTIR spectra were recorded on a Spectrum Two instrument in ATR mode over the 400–4000&#xa0;cm<sup>−1</sup> range, and <sup>13</sup>C NMR spectra were acquired using a JEOL 500&#xa0;MHz spectrometer in D<sub>2</sub>O, providing experimental validation of the simulation-derived structural insights.</p>

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Molecular dynamics simulations and spectroscopic study of the microstructural solvation shells, transport, and dielectric properties of the {K2CO3–H2O} system at various concentrations

  • 期刊论文

  • 发表日期：

    2026年1月7日

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  • Ayoub Lahmidi,
  • Soumia Chliyah,
  • Sanaa Rabii,
  • Samir Chtita,
  • M’hammed EL Kouali,
  • Abdelkbir Errougui

摘要

Context

Understanding the behavior of potassium carbonate (K2CO3) in water is essential for improving its performance in various chemical and industrial applications. The physicochemical properties of K2CO3 aqueous solutions determine its reactivity, stability, and efficiency in processes such as CO2 capture and alkaline electrochemistry. In this study, we combined molecular dynamics simulations and spectroscopic experiments to elucidate the microstructural, dynamic, and dielectric behaviors of the {K2CO3–H2O} system across concentrations ranging from 0.11 to 1.07 mol.kg−1 at T = 298.15 K. The analyses reveal strong ion-water correlations, coordination changes within hydration shells, and concentration-dependent variations in ionic mobility and dielectric constant. Experimental FTIR and NMR measurements validated the simulated structures and provided deeper insights into the hydration mechanisms and ion–water interactions governing the dissolution and transport properties of K2CO3 in water.

Methods

Classical molecular dynamics simulations were performed using GROMACS 2020.6 with the CHARMM36 force field for ions and the SPC/E water model. Ionic interactions were modeled through long-range Coulombic and short-range Lennard–Jones potentials. Systems spanning 0.11–1.07 mol.kg−1 were equilibrated for 100 ns in both NVT and NPT ensembles, followed by 100 ns production runs at 298 K and 1 bar using the PME algorithm for electrostatics. FTIR spectra were recorded on a Spectrum Two instrument in ATR mode over the 400–4000 cm−1 range, and 13C NMR spectra were acquired using a JEOL 500 MHz spectrometer in D2O, providing experimental validation of the simulation-derived structural insights.