Desalination due to Electrical Image Forces

TL;DR

This paper investigates how electrical image forces near metallic walls can cause high local salt concentrations and potential desalination by flowing saltwater between plates, due to image charge effects and dielectric variations.

Contribution

It introduces a novel mechanism where electrical image forces induce salt accumulation near walls, suggesting a new desalination method based on these electrostatic effects.

Findings

Salt ion concentration near walls can exceed solubility limits due to image forces.

Dielectric constant variation creates attractive image potentials near the wall.

Flowing water between plates can facilitate salt removal via these electrostatic effects.

Abstract

It will be shown that for a solution of salt dissolved in water in contact with a metallic wall, the concentration of salt ions (both positive and negative) within a few Angstroms of the wall can be large enough to exceed the solubility limit of the salt, as a result of electrical image charge forces. In addition, since the dielectric constant of water increases from 2.1 at the wall to 81 at about a nanometer from a solid wall, there will be an attractive image potential near the plane on which this increase of the dielectric constant occurs. The possible existence of these image potentials suggests that the salt can be removed from the water by making salt water flow between an array of parallel solid plates..