Influence of inorganic and organic salts on the hydration mechanism of montmorillonite based on molecular simulation

Lianjun Yang; Bo Xiang; Haisong Zhao; Kai Wu; Enlong Liu; Ge Zhang

doi:10.1038/s41598-023-36137-w

Influence of inorganic and organic salts on the hydration mechanism of montmorillonite based on molecular simulation

Sci Rep. 2023 Jun 5;13(1):9090. doi: 10.1038/s41598-023-36137-w.

Authors

Lianjun Yang¹, Bo Xiang², Haisong Zhao², Kai Wu², Enlong Liu³, Ge Zhang⁴

Affiliations

¹ State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, China.
² Sichuan Provincial Transport Department Highway Planning, Survey, Design and Research Institute, Chengdu, 610041, Sichuan, China.
³ State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, China. liuenlong@scu.edu.cn.
⁴ Key Laboratory of Geological Hazards On Three Gorges Reservoir Area, Ministry of Education, China Three Gorges University, Yichang, 443002, Hubei, China.

Abstract

The molecular dynamics method is used to further reveal, from the molecular point of view, the mechanisms of salt inhibiting the hydration of Na-MMT. The interaction between water molecules, salt molecules, and montmorillonite are calculated by establishing the adsorption models. According to the simulation results, the adsorption conformation, interlayer concentration distribution, self-diffusion coefficient, ion hydration parameters, and other data are compared and analyzed. The simulation results show that the volume and basal spacing increase in a stepwise manner with the increase of water content, and water molecules have different hydration mechanisms. The addition of salt will enhance the hydration properties of compensating cations of montmorillonite and affect the mobility of particles. The addition of inorganic salts mainly reduces the adsorption tightness between water molecules and crystal surfaces, thereby reducing the thickness of water molecules layer, while the organic salts can better inhibit migration by controlling interlayer water molecules. The results of molecular dynamics simulations reveal the microscopic distribution of particles and the influence mechanism when the swelling properties of montmorillonite are modified by chemical reagents.