Deionized water is water that is free of salt ions and trace elements, such as sodium, calcium, iron, copper, chlorides, sulfates, etc. Deionization is a process that uses specially made ion exchange resins, which exchange hydrogen cations and hydroxide ions with salt ions, to form water.
The pH of deionized water during its production ranges between 6.5-7.5. Because the storage tanks, during the filling, come in contact with the ambient air, carbon dioxide is absorbed and the pH value drops close to 5.7.
Deionized water is used for medicinal, medical and laboratory purposes and is a major ingredient in many shampoos, cosmetics and perfumes. It is also used in the field of microelectronics, in the preparation of electrolytes for acidic and alkaline batteries and generally in any industrial process that requires chemically pure water.