The ion exchange mixed bed equipment system is a traditional water treatment process that uses anion and cation exchange resins to replace various anions and cations in water. The anion and cation exchange resins can be combined in different proportions to form an ion exchange cation bed system, an ion exchange anion bed system, and an ion exchange mixed bed (complex bed) system. The mixed bed (complex bed) system is usually used as a terminal process for producing ultrapure water and high-purity water after water treatment processes such as reverse osmosis. It is currently one of the irreplaceable means for preparing ultrapure water and high-purity water. The effluent conductivity can be below 1uS/cm, and the effluent resistivity can reach 1M Ω. cm or more. Depending on the water quality and usage requirements, the effluent resistivity can be controlled between 1-18.2 M Ω. cm. Ion exchange technology is widely used in the field of water treatment for the preparation of industrial ultrapure water and high-purity water, including electronic and power ultrapure water, chemical, electroplating ultrapure water, boiler feedwater, and pharmaceutical ultrapure water. Compared with the reverse osmosis devices introduced in recent years, it has the ability to thoroughly remove ionic impurities; Low requirements for water pretreatment; Advantages such as low equipment cost. There is currently no substitute equipment for ion exchange technology in the preparation of high-purity water. When the total salt content of the incoming water is below 400mg/l, the effluent quality should be between 1.0-0.2us/cm according to different user requirements. If the total salt content of the influent is above 500mg/l, it can be combined with an electrodialysis device for desalination, and the effluent quality can also be improved.

Working principle of resin in ion exchange mixed bed equipment
By using ion exchange method, cations and anions in the form of ions can be removed from water. Sodium chloride (NaCl) represents inorganic salts in water, and the basic reaction of water desalination can be expressed by the following equation:
1. Cation exchange resin: R-H+Na+R-Na+H+
2. Anion exchange resin: R-OH+Cl-R-Cl+OH-
3. The overall reaction equation for cation and anion exchange resins can be written as: RH+ROH+NaCl - RNa+RCL+H2O
From this, it can be seen that NaCl in the water has been replaced by H+and OH - on the resin, while the reaction product is only H2O, thus achieving the effect of removing salts from the water.