Molecular Simulations of Membrane Based Separations of Supercritical Electrolyte Solutions

Abstract

Computer simulations of solutions of electrolytes (NaCl and KCl) in supercritical water undergoing membrane based separations have been carried out. These studies used a technique developed recently, in which the system is maintained at steady state by periodically recycling the solvent molecules that permeated the membrane. Our results showed that ionic clusters, formed as a result of water molecules surrounding the ions, play a significant role in these separations. The effect of the main osmotic driving forces, such as pressure, temperature, concentration, and electric fields on the rate of permeation across the membrane was studied. In addition, we also looked at the effect of changes in the pore size and the attractive force between the membrane and solvent/solute. Finally, we examined the stability of the ionic clusters in these simulations.