**3. Electrodialysis**

The scientific principle that sustains electrodialysis (ED) is the electrical attractions between ions and electrodes of opposite electric charge. This phenomenon suits desalination since the dissolved particles in salted water are electrically charged (positive and negative ions). In ED desalination selective membranes are used to "sift" the ions. Some retain the positive ions and allow the negative ones to pass through, while others perform with the inverse characteristic. Membranes with inverse characteristic are placed alternately between the positive and negative electrodes. This configuration yields two separate outlet fluxes, drinking water, and brine. **Figure 4** depicts a conventional ED desalination module. ED is mostly used to desalinate brackish water.

**Figure 4.** *Electrodialysis membrane configuration. Source [1].*
