The working principle of EDI is shown in the figure. A certain number of EDI units are separated by grids in the EDI membrane block to form a concentrated water chamber and a fresh water chamber. And cathode/anode electrodes are arranged at both ends of the unit. Under the impetus of direct current, the anion and cation in the water flow passing through the fresh water chamber respectively migrate to the concentrated water chamber through the anion exchange membrane and are removed in the fresh water chamber. As shown below:

The electric field dissociates the water molecules in the influent into H+ and OH- at the interface of the ion exchange resin, and continuously regenerates the anion and cation exchange resins in the fresh water chamber. Anions and cations in the ion exchange resin are attracted by the corresponding positive and negative electrodes in the regeneration process, and migrate to the corresponding ion membrane direction through the cation and anion exchange resin. When these ions enter the concentrated chamber through the exchange membrane, H+ and OH- recombine into water. The generation and annihilation of H+ and OH- and the migration of anions and cations are the mechanism of continuous regeneration of ion exchange resin.

The role of EDI module:

Ultrapure water is often used in microelectronics industry, semiconductor industry, power generation industry, pharmaceutical industry and laboratory. EDI pure water can also be used as distilled water for pharmaceuticals, water for food and beverage production, process water for chemical plants and other ultra-pure water applications.