working principle
In the EDI component, a certain number of EDI units are separated by a mesh to form a concentrated water chamber. Negative/positive electrodes are also installed at both ends of the unit group. Driven by direct current, the anions and cations in the water flow of the fresh water chamber pass through the cation exchange membrane and enter the concentrated water chamber, where they are removed. And the ions are carried out of the system by the water in the concentrated water chamber, becoming concentrated water EDI equipment generally uses reverse osmosis (R0) pure water as EDI feed water. The pure water resistivity of R0 is generally 40~2 μ S/cm (25 ℃). EDI pure water resistivity can reach up to 18M Ω· cm (25 ℃), but depending on the purpose of deionized water and system configuration settings, EDI pure water is suitable for preparing pure water with resistivity requirements between 1-18.2M Ω· cm (25 ℃).
Advantages of EDI
1. The effluent quality is very stable;
2. Capable of continuous operation and producing ultra pure water that meets user requirements;
3. No need for acid-base regeneration, no wastewater discharge;
4. Modular production, fully automated control;
5. No need to shut down due to regeneration;
6. Compact equipment structure and small footprint;
7. Low operating and maintenance costs;
8. Simple operation and low labor intensity
Scope of application
EDI, as a device for producing ultrapure water and a secondary desalination equipment after reverse osmosis, can produce up to 10-18.2 M Ω CM. EDI equipment does not require the regeneration of chemical agents and can operate continuously. In specific applications, simply adjusting the operating current of EDI can change its effluent quality. Therefore, it is widely used in the microelectronics industry, semiconductor industry, power generation industry, and laboratories. It can also be used as distilled water, water for food and beverage production, make-up water for boilers in power plants, and other applications of ultrapure water.
