What is the principle behind electrodialysis?

Electrodialysis operates on the principle of selectively allowing ions to pass through membranes that distinguish between cations and anions. This process uses cation-selective membranes, which permit only positively charged ions (cations) to pass, and anion-selective membranes, which allow only negatively charged ions (anions) through. By applying an electric field across these membranes, ions are driven toward their respective electrodes, facilitating the separation of ions from water and the concentration of salts on one side while producing deionized water on the other.

This selective passage of ions is crucial in applications such as desalination, water purification, and the recovery of valuable resources, demonstrating the effectiveness of electrodialysis in efficiently removing specific ions without needing chemical reagents or extensive filtration processes.