1) EDI concept

       Electrodeionization EDI (Electro-deionization, referred to as EDI) is a new preparation of pure water and ultra pure water technology. The technology will electrodialysis and ion exchange technologies integration, through the anion and cation exchange membrane on the anions and cations through the role of the choice of ion exchange resin and ion exchange in the DC electric field to achieve the directional migration of ions, thus completing the the depth of water desalination, producing resistance up to 15 ~ 18.2 MΩ · cm ultra-pure water.
2) Work 
    There will be a natural source of sodium, calcium, magnesium, chloride, nitrate, bicarbonate and other solutes. These compounds by the negatively charged anions and positively charged cations. By reverse osmosis pretreatment, 95% -99% of the ions can be removed. Reverse osmosis water production is the general scope of the resistivity of 0.05-1.0M? · Cm, the conductivity of reverse osmosis water production generally range 20-1μS/cm. According to the situation in practical applications, EDI electrical resistivity of deionized water, the scope of products is generally 5 ~ 18.2 MΩ · cm. In addition, the raw water and may also include other trace elements, dissolved gases (such as CO2) and some weak electrolyte (such as boron, silica, etc), these impurities must be removed in water desalination industry. However, pretreatment of reverse osmosis for the removal of these impurities less effective. Thus, EDI's role is to remove the electrolyte (including weak medium), the resistivity of the water from 0.05 ~ 1.MΩ · cm increased to 5 ~ 18.2 MΩ · cm.
3) EDI technology deal with the process of the three mutual
1, reverse osmosis pure water pure water EDI room, the water in the ion and EDI modules in place of ion exchange resin ion exchange, and thus from the water off;
 2, was the exchange of ions by electrical attraction, cation through cation exchange membrane to the cathode migrate through the anion ion exchange membrane to the anode shift, and enter the room so dense water removed from the water. Ion concentration of water into the chamber, due to the cation can not pass through anion exchange membrane, so it will be trapped in the dense water room, the same anion can not pass through cation exchange membrane, trapped in the dense water chamber, so that ions will be trapped down With the concentration of water was discharged module; At the same time, due to water of the ions are continually removed, then the purity of water will continue to improve, and finally by the module out of the purity of water can reach close to the theoretical level.
 3, water molecules under the action of the electric dissociation constant for the H + and OH-, H + and OH-will allow the sun to be consumed, anion exchange resins are continuously regenerated.
    The first two processes can improve water quality EDI module, and the last regeneration process because of the regeneration reaction of Er Shi deterioration in water quality, but the regeneration process is a long-term continuous packed bed electrodialysis operation necessary, so that the choice suitable working conditions, we can ensure access to quality water, while maintaining the self-regeneration of ion exchange resins.
4) EDI technical merit 
  l without acid-base regeneration, no chemicals used, no acid waste water, the production process without any pollution, is a cleaner production;
 l do not stop recycling, water quality and stable continuous production of highly pure water;
 l reliable, and reduce operating and maintenance costs;
 l do not need to send specialized personnel to guard, is easy to realize automatic control device;
 l equipment, small footprint, reduce the plant construction area, construction costs, space saving investments;
 

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