Explain in detail the two important qualities of ultrapure water

Now the most stable and convenient way to prepare pure water and ultrapure water is through pure water and ultrapure water system. Since the advent of the world’s first ultrapure water system, the design and production concept of ultrapure water systems has been constantly improving around “the best water quality, the most stable water quality”.

The best water quality

1. Common impurities in natural water

Including soluble inorganic matter, organic matter, particulate matter, microorganism, soluble gas, etc. Pure water / ultrapure water systems are all about removing these impurities as thoroughly as possible.

2. The main process of purifying water

At present, the commonly used process methods for purifying water quality include distillation, reverse osmosis, ion exchange, filtration, adsorption, and ultraviolet oxidation. At the same time, we can roughly divide the water purification process into three major steps, pretreatment (to produce pure water), ion exchange (to produce 18.2MΩ-cm ultrapure water) and posttreatment (to produce ultrapure water that meets special requirements) water). According to the quality of the influent water and the requirements for the water quality of the effluent, the method and process used in each step are determined.

3. preprocessing

It mainly includes a pretreatment unit and a reverse osmosis (RO) unit. Since the pretreated water will be further purified by reverse osmosis, it is necessary to remove impurities that affect the reverse osmosis membrane as much as possible; mainly including large particulate matter, residual Chlorine and calcium and magnesium ions. The point to be explained here is that different treatment units must be equipped according to the difference of the influent water quality. Most water purifier manufacturers cannot help customers solve this problem very well, which will lead to unsatisfactory results in subsequent purification and shorten the life of major components such as reverse osmosis membranes.
Reverse osmosis uses a high-pressure pump to provide a high-concentration solution with a pressure greater than the osmotic pressure difference, and water molecules will be forced to pass through the semi-permeable membrane to the low-concentration side. Reverse osmosis can filter 90%-99% of inorganic ions. Most of the pollutants in the water, because of its outstanding purification efficiency, reverse osmosis is a very effective technology for water purification systems, because reverse osmosis can remove most of the pollutants, so it is often used as a pre-treatment method, Can significantly prolong the use time of deionization exchange column. In view of the fact that reverse osmosis is very critical in the water purification process and the replacement price of reverse osmosis membrane is high, we recommend that users must choose an ultrapure water system that has a protective function for reverse osmosis membranes.

4. ion exchange

Ion exchange means that the positive ions in the water are exchanged with the H+ ions in the ion exchange resin, and the negative ions in the water are exchanged with the OH- ions on the ion exchange resin, so as to achieve the purpose of purifying water. By removing ions by ion exchange, almost all ionic substances can be removed theoretically. At 25°C, the effluent resistivity reaches 18.2MΩ-cm. The quality of the ion-exchanged effluent mainly depends on the quality of the ion-exchange resin and the exchange efficiency of water and resin in the exchange column.
It should be noted that the ion exchange method can effectively remove ions, but it cannot effectively remove most of the organic matter or microorganisms, while the microorganisms can attach to the resin and use the resin as a medium, so that the microorganisms can grow rapidly and generate heat. Therefore, it needs to be designed and used in conjunction with other purification methods, that is, the post-processing part we will discuss below.

5. post-processing

It mainly produces ultra-pure water with low organic matter type and low heat source type according to the special requirements of customers. There are various treatment methods for different requirements, such as ultrafiltration filtration for removing heat sources, dual-wavelength UV oxidation for reducing total organic carbon (TOC) in water, and microfiltration for removing bacteria.
Ultrafiltration (UF) membrane is a molecular sieve, which is based on size, allowing the solution to pass through a very fine filter membrane to achieve the purpose of separating molecules of different sizes in the solution, which can reduce the heat source content in ultrapure water to 0.001EU /ml or less. The dual-wavelength UV oxidation method utilizes photo-oxidation of organic compounds to reduce the total organic carbon concentration in ultrapure water to below 5ppb.

The most stable water quality

It is only the first step that the ultrapure water system can produce high-quality ultrapure water. For users, it is the most concerned issue for users to be able to maintain high water quality as long as possible. At present, most manufacturers emphasize to let customers pay attention to the details of use, and often change accessories and consumables, but there are not many improvements from their own side.

The main application fields of ultrapure water are:

  1. Water for animal and plant cell culture
  2. water for various medical biochemical instruments, analyzers, and hemodialysis instruments
  3. Analytical reagents and medicines are prepared with dilution water;
  4. Physiological, pathological and toxicological experimental water;
  5. Purified water and high-purity water for hospitals, pharmaceutical preparation rooms and central laboratories:
  6. Atomic absorption spectroscopy with water;
  7. test tube baby water;
  8. various high performance liquid chromatography, ion chromatography water;
  9. other various laboratory water and medical water.

Xi’an CHIWATEC Water Treatment Technology is a high-tech enterprise specialized in various water processing devices. Aside from these individual products, which cover a number of types and series, we can also help with related comprehensive engineering projects. Thanks to our hard work and dedication upon our founding, we are now one of the fastest-developing water treatment equipment manufacturers in Western China.

Further reading

Modified PVC UF system

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