Simulation of Ion Distribution on both Sides of Insulation Film in Saltwater under Static Electric Field

Abstract

The world is facing a severe crisis of fresh water shortage. Seawater desalination technology is an ideal answer to this crisis. However, the conventional desalination technologies consume too much energy. New desalination methods are required to reduce the energy consumption. This paper proposes an idea for saltwater desalination based on the ions of contrary sign which attract each other on both sides of a thin insulation film in a high-voltage static electric field. In an insulation pipeline with saltwater, a piece of thin insulation film is installed vertically to the electric field. The positive ions were pumped onto the positive side of the film while the negative ions were pumped onto the negative side of it. Both ions accumulate at both sides of the film at the aid of electric field. The thinner is the insulation film, the stronger of the attractive force between positive and negative ions at opposite sides of the film and the higher the ion concentration on both sides of it. First, a model based on this idea was introduced. Then, four factors were simulated to reveal their effects on the ion distribution characteristics, including the salt concentration, the length of the pipeline, the electric field intensity, and the film thickness. The simulation results show that the desalination idea is practice to eliminate the dissolved ions in salt water and produce fresh water if the insulation film is thin enough and the electric field intensity is strong enough. The electric field only exerts electric force onto not the majority of water molecular but the minority of ions, so this method consumes much less energy than the conventional desalination methods.