Electrodeionization Commercial Water Purification Plant Electrodialysis Concentration Overcomed

Electrodeionization Commercial Water Purification Plant Electrodialysis Concentration Overcomed

^{EDI system
Electrodeionization (EDI) technology is an organic combination of traditional ion exchange and electrodialysis technology. It not only retains the advantages of continuous leaching of electrodialysis and deep desalination of ion exchange resin, but also overcomes the electrodialysis concentration. The adverse effects caused by differential polarization and the trouble of acid-base regeneration of ion exchange resins and environmental pollution caused. Exchanging the anion and cation of the adsorbed feed water by the ion exchange resin, and simultaneously exchanging the exchanged adsorbed anions and cations through adjacent selective anion and cation exchange membranes under the action of electrodialytic DC electric field, due to The concentration polarization polarizes the water to dissociate, generating H+ and OH-, and the effect of automatic electric regeneration on the ion exchange resin. The whole process is equivalent to continuous regenerative mixed bed ion exchange, which can continuously produce pure water continuously. High purity water.
The EDI technology combines two mature water treatment technologies, ion exchange and electrodialysis, to achieve continuous dewatering process. Unlike electrodialysis, EDI is filled with ion exchange resin in the fresh water chamber. The presence of ion exchange resin allows ion exchange to minimize the amount of ions in the water. Second, it can greatly enhance ion migration. Speed, the continuous implementation of the process.}

^{A basic EDI unit-membrane pair is formed by a concentrated water chamber, a cation exchange membrane, a fresh water chamber and an anion exchange membrane. Several or dozens of membrane pairs constitute a desalting unit-module, and the ends are positive and negative electrodes and The clamping plate is filled with an anion and cation exchange resin in the fresh water chamber. The ion exchange resin functions as ion exchange and ion transport, while the ion exchange membrane has selective permeation of ions. The anion exchange membrane only allows anion to permeate and does not allow cations to pass through; while the anode membrane only allows cations to permeate, Anion permeation is allowed. Moreover, the ion exchange membrane is impervious to water.
When the feed water passes through the fresh water chamber, the cations, anions and ion exchange resins in the feed water are ion exchanged, and the cations and anions in the water are exchanged and transferred to the ion exchange resin, and the exchanged cations and anions are again at the ends of the direct current. Under the action of the field, it migrates along the surface of the resin ball and enters the concentrated water chamber through the ion exchange membrane. The resin on the resin leaves the resin, enters the water and combines into water, thereby achieving the purpose of removing ions in the feed water and preparing pure water. At the same time, under the action of a higher potential gradient, the water will be electrolyzed to produce a large amount of sum, which can replace the ion exchange resin for continuous regeneration instead of acid or alkali. Therefore, the ion exchange resin in the EDI module does not need to be regenerated with chemicals, achieving a continuous deionization process. In fact, the fresh water chamber of the EDI module is equivalent to a mixed bed ion exchange column that is regenerated while working (exchange). Therefore, the EDI module can work continuously, the ion exchange resin in the module will not be saturated, and it is not necessary to stop the operation. Regenerate the resin and obtain high quality pure water without causing environmental pollution.}