Density Functional Theory Study of Water Molecule Adsorption on the α-Quartz (001) Surface with and without the Presence of Na+, Mg2+, and Ca2+

Abstract

Adsorption of the single water molecule on the α-quartz (001) surface with and without the presence of Na+, Mg2+ and Ca2+ was analyzed utilizing the density functional theory method. Our results demonstrate that the optimal adsorption configuration of the single water molecule on the α-quartz (001) surface lies in the bridge being configured with two formed hydrogen bonds. These were Os-Hw and Hs-Ow (s and w represent, respectively, surface and water molecules), while the main hydrogen bond is Hw-Os. Furthermore, the corresponding adsorption energy was -72.60 kJ/mol. In this study, the presence of metal ions helped to deflect the spatial position of the water molecule, and the distance between Ow and Hs was altered significantly. Furthermore, the charge transfer between the interacting atoms increased in the presence of metal ions, wherein the effects of Ca2+ and Na+ proved to be significant compared to Mg2+. Finally, it emerged that metal ions interacted with the water molecule and were subsequently adsorbed on the α-quartz (001) surface. This occurred due to the electrostatic attraction, consequently impacting the hydration characteristics of the quartz surface.