Influence mechanism of hydrated cations on surface hydration of slime mineral particles

To elucidate the microscopic mechanisms underlying the impact of hydrated cations on the surface hydration of slime mineral particles (specifically, kaolinite and quartz, the primary minerals in slime), this study focused on constructing two common hydrated cations in slime water: [Na(H2O)5]+ and [Ca(H2O)8]2+. Using density functional theory, the adsorption of these two hydrated cations on the surfaces of kaolinite (001), (\begin{document}$ 00\overline 1 $\end{document}) and α-quartz (001), as well as their competitive adsorption with water molecules were simulated. The simulation results revealed that the adsorption energy of hydrated cations on all three surfaces was over 50% lower than that of water molecules. The adsorption stability on mineral surfaces was as follows: α-quartz (001) surface > kaolinite (001) surface > kaolinite (\begin{document}$ 00\overline 1 $\end{document}) surface. The adsorption energy of the competitively stable configuration was 34%–57% lower than that of a single hydrated cation