MOLECULAR DYNAMICS STUDY OF WATER VAPOR ABSORPTION INTO AN AQUEOUS ELECTROLYTE SOLUTION

In order to investigate the dynamic process of the absorption of water vapor into aqueous electrolyte solution, molecular dynamics simulations were carried out under nonequilibrium conditions. The two boxes at liquid-vapor equilibrium at different saturation pressure are coupled. One box contains water and the other box contains aqueous electrolyte solution. The variables are the temperature of the water, the temperature and concentration of the aqueous electrolyte solution, and the pressure difference between the two boxes. The absorption rate was calculated and some molecular pictures are reported. On the molecular scale, ions are negatively adsorbed at the surface, particularly in weak aqueous electrolyte solution, and highly concentrated aqueous electrolyte solution is effectively ''frozen'' and cannot rapidly adjust to the incident water vapor molecules. These structural and dynamical properties affect the absorption rate.