EDI (Electrodeionization) is a revolutionary water treatment technology, which cleverly combines electrodialysis technology and ion exchange technology, and can continuously produce high-quality pure water without acid and alkali. It has professional technology, easy operation, and good environmental protection characteristics. It represents an industry direction and can be widely used in electric power, medicine, chemical industry, electronics and other industries. Its appearance is a revolutionary progress in water treatment technology, which marks that the water treatment industry has finally entered the ranks of green industries in an all-round way.
The entire technological process of ultrapure water is pretreatment first, then dosing with anti-virus, and then through RO reverse osmosis system, and then use EDI equipment to produce ultrapure water.
Since ultra-pure water has relatively high requirements on the content of BOD and TOC in water quality, two-stage reverse osmosis is generally used, and EDI technology is often used in the latter process. EDI has advantages in pure water preparation technology.
EDI is used as equipment for producing ultrapure water, and as a secondary desalination equipment after reverse osmosis equipment, which can produce up to 10-18.2MΩ.CM. EDI equipment does not require regeneration of chemicals and can run continuously. In specific applications, only adjusting the operating current of EDI can change the water quality of its effluent. Therefore, it is widely used in microelectronics industry, semiconductor industry, power generation industry, pharmaceutical industry and laboratories. It can also be used as pharmaceutical distilled water, water for food and beverage production, make-up water for boilers in power plants, and ultrapure water for other applications.
Continuous Electrodeionization (EDI, Electrodeionization or CDI, continuous electrodeionization) is to use mixed ion exchange resins to adsorb anions and cations in the feed water. process of removal. In this process, the ion exchange resin is continuously regenerated electrically, so there is no need to use acid and alkali to regenerate it. This new technology can replace the traditional ion exchange device to produce ultrapure water up to 18M-CM. It can also be described clearly: EDI uses anion and cation membranes in the form of symmetrical stacking, and anion and cation resins are sandwiched between the anion and cation membranes, and the anion and cation are exchanged under the action of DC voltage respectively. At the same time, under the action of the voltage gradient, water will undergo electrolysis to generate a large amount of H+ and OH-, and these H+ and OH- will continuously regenerate the anions and cations in the middle of the ion membrane. Due to the constant exchange-regeneration of EDI, the pure water is getting higher and higher, so it is easy to produce high-purity ultra-pure water.
EDI technology is a new type of membrane separation technology formed by the organic combination of electroosmosis and ion exchange. With the help of the ion exchange effect of ion exchange resin and the selective permeation effect of anion and cation exchange membranes on anion and cation, under the action of DC electric field, the directional migration of ions is realized, thereby completing the deep desalination of water. Since ion exchange, ion migration and ion exchange resin electrical regeneration occur together, it is like a mixed bed ion exchange resin column regenerated while working, which can continuously produce high-quality pure water and high-purity water, so it is also called continuous deionization. (continuous deionization, referred to as CDI).
System process
Tap water-->Pretreatment-->Activated Carbon-->Security Filtration-->Reverse Osmosis-->Electrodeionization
Main technical features and performance indicators
(1) The desalination rate is greater than 99.9%, and the efficiency is much higher than that of two-stage reverse osmosis and simple ion exchange.
(2) Compared with the traditional ion exchange desalination method, it saves more than 95% of the resin
(3) The ion exchange resin does not need to be regenerated with acid and alkali, which saves a lot of acid and alkali and cleaning water, and reduces labor intensity.
(4) Clean production, no waste water treatment problem, good for environmental protection.
(5) It has a high degree of automation and is easy to maintain, and can be designed as a complete membrane technology high-purity water production line.
(6) The resistivity of the produced water is 15-18MΩ·cm, pH6.5-7.0, silicon <1.0ppb, effectively sterile.
(7) Small footprint, continuous operation of a single system, no need to build a backup system.
scope of application
Industrial systems: medicinal pure water, electronic grade water, power generation boiler supply water, electroplating, electrophoretic coating water, photosensitive film, electroplating parts cleaning water, process water (demineralized water) required in petroleum, chemical, electroplating, battery, metallurgy, machinery and other industrial systems .
Medical and laboratory fields: hemodialysis, artificial kidney, amino acid analysis, cell and tissue culture, chemical and biochemical reagent preparation, buffer solution and pharmaceutical preparation preparation, high-purity reagent production, utensil washing, liquid phase, gas phase, ion chromatography, atomic absorption, emission spectrum, environmental protection experimental analysis.
