Molecular insights on the influence of temperature and metal ions on the hydration of kaolinite (001) surface

ABSTRACT

In the present research, various divalent and monovalent metal salt solutions (NaCl, KCl, MgCl2 and CaCl2) were added into the kaolinite-water system to explore its impact on the surface hydration of kaolinite. The hydration layers’ density and adsorption energy between kaolinite and water molecules were gradually decreased with an increase in temperature from 280 to 330 K. The addition of metal ions had a great influence on the hydration of the kaolinite surface. While the adsorption energy and structure of hydration layers in the kaolinite-water-ion system was unchanged when the ion concentration reaches 0.8 M. The adsorption energy between kaolinite and divalent ions was greater than between kaolinite and monovalent ions.

GRAPHICAL ABSTRACT

KEYWORDS:

• Kaolinite surface
• hydration layer
• monovalent ions
• temperature
• adsorption equilibrium

Acknowledgements

This work was supported by the Zhaoqing Science and Technology Project (2018N006), The Technology Innovation Project of Zhaoqing (201904030103) and the Guangdong College Students’ Innovative Project (X201910580158).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by The Guangdong College Students’ Innovative Project [grant number X201910580158]; Zhaoqing Science and Technology Project [grant number 2018N006]; The Technology Innovation Project of Zhaoqing [grant number 201904030103].