Common impurities in natural water include soluble inorganic substances, organic matter, particulate matter, microorganisms, and soluble gases. Ultrapure water machine is to remove these impurities as thoroughly as possible. At present, the commonly used methods for purifying water quality include distillation, reverse osmosis, ion exchange, filtration, adsorption, and ultraviolet oxidation. Ultrapure water machine can generally divide the water purification process into 4 major steps, pretreatment (primary purification), reverse osmosis (production of pure water), ion exchange (which can produce 18.2MΩ.cm ultrapure water) and terminal Treatment (production of ultrapure water meeting special requirements).
1) Pretreatment Since the pretreated water will be further purified by reverse osmosis, it is necessary to remove impurities that have an effect on the reverse osmosis membrane; mainly including large particulate matter, residual chlorine and calcium ion magnesium ions. The point of explanation is that different processing units must be specifically equipped according to the difference in the quality of the influent water. Most pure water machine manufacturers are not able to solve this problem very well, which will lead to subsequent purification not achieving the desired results and shortening the life of major components such as reverse osmosis membranes and ultra-purification columns. In order to solve this problem well, the precision filter, activated carbon adsorption filter and softening resin are designed to remove large particles in the water, residual chlorine and calcium ion magnesium ions to achieve the best pretreatment effect. The timely replacement of pre-treatment consumables (the price is relatively low) is very important for the long-term stable operation of ultra-pure machines and the protection of core components.
2) Reverse osmosis reverse osmosis is to use a high pressure pump to provide a high pressure solution with a pressure greater than the osmotic pressure difference, water molecules will be forced through the semipermeable membrane to the low concentration side, reverse osmosis can filter out 90%-99% Most of the contaminants, including inorganic ions, are a very effective technique for water purification systems because of their superior purification efficiency. Because reverse osmosis can remove most of the dirt, it is often used as a former The channel treatment method can significantly prolong the use time of the deionization column. In view of the fact that reverse osmosis is very critical in the purification process of water quality and the replacement price of reverse osmosis membrane is relatively high, we recommend that you choose an ultrapure water machine that has a protective function against reverse osmosis membranes. In order to maximize the service life of the reverse osmosis membrane and improve the filtration efficiency of the reverse osmosis membrane, a unique technology is adopted, combined with the leading reverse osmosis flow restriction design, the flow valve is limited to the flow valve, so that the reverse osmosis membrane is always immersed in the water, so as not to It affects life due to drying out. Extending the life of the reverse osmosis membrane is to ensure the quality of the effluent, and also to increase the price of the ultrapure water system.
3) Ion exchange ion exchange is the exchange of positive ions in water with H + ions in the ion exchange resin, and the negative ions in the water exchange with the OH - ions on the ion exchange resin to achieve the purpose of purifying water. By ion exchange, it is theoretically possible to remove almost all ionic species. At 25 ° C, the effluent resistivity reaches 18.2 MΩ·cm. The quality of the ion exchange effluent depends mainly on the quality of the ion exchange resin and the water in the exchange column. Exchange efficiency with resin.
4) Terminal treatment mainly produces ultra-pure organic type, aseptic type, and non-heat source type ultra-pure water according to special requirements. There are various treatment methods for different requirements, such as ultrafiltration filtration method for removing heat source, dual-wavelength ultraviolet oxidation method for reducing total organic carbon (TOC) in water, and microfiltration to remove bacteria. Ultrafiltration (UF) film is a molecular sieve, which is based on the size of the solution, allowing the solution to pass through a very fine filter to achieve the purpose of separating molecules of different sizes in the solution. The heat source content in ultrapure water can be reduced to 0.001 EU. /ml below. The dual-wavelength ultraviolet oxidation method can utilize photooxidation of organic compounds to reduce the total organic carbon concentration in ultrapure water to below 5 ppb.
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