Preparation process of pure water and ultrapure water

Best Water Quality

1. Common impurities in natural water

Including soluble inorganic matter, organic matter, particulate matter, microorganisms, soluble gases, etc. Pure water, ultrapure water system is to remove these impurities as thoroughly as possible.

2. The main process of purifying water quality

Currently, the commonly used water purification processes include distillation, reverse osmosis, ion exchange, EDI, and ultraviolet oxidation. At the same time, we can roughly divide the water purification process into three major steps, pre-treatment (to produce pure water), ion exchange (to produce 18.2MΩ-cm ultra-pure water) and post-treatment (to produce ultra-pure water that meets special requirements) water). According to the water quality of the influent water and the requirements for the water quality of the effluent water, determine the method and process used in each step.

There are 3 major steps in the purification process:

1. Pretreatment

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 particles, residual Chlorine and calcium ions magnesium ions. The point to be explained here is that different treatment units must be equipped according to the difference of influent water quality. Most water purifier manufacturers cannot help customers solve this problem well, which will lead to the failure of subsequent purification to achieve ideal results and shorten the life of major components such as reverse osmosis membranes.
Chiwatec ultra-pure water system solves this problem very well. We design and produce wire-wound filters, activated carbon adsorption filters and softening resins to remove large particles, residual chlorine and calcium ions and magnesium ions in the water in a targeted manner to achieve the best good preprocessing effect.
Reverse osmosis uses a high-pressure pump to provide a pressure greater than the osmotic pressure difference to a high-concentration solution. Water molecules will be forced to pass through a semi-permeable membrane to the low-concentration side. Reverse osmosis can filter out 90%-99% of inorganic ions in the 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, it is often used as a pre-processing method. Can significantly prolong the use time of the deion exchange column. In view of the fact that reverse osmosis is very critical in the process of water purification and the replacement price of reverse osmosis membrane is relatively high, we recommend that users must choose an ultrapure water system that can protect the reverse osmosis membrane.
In order to prolong the service life of the reverse osmosis membrane as much as possible and improve the filtration efficiency of the reverse osmosis membrane, chiwatec ultrapure water system adopts advanced unique technology, combined with the leading reverse osmosis flow limiting design, the flow limiting valve at the water outlet makes the reverse osmosis The membrane is always soaked in water, so the lifespan will not be affected by drying out. Prolonging the life of the reverse osmosis membrane ensures the quality of the effluent water, and at the same time improves the cost performance of the ultrapure water system.

2. 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. Removing ions by ion exchange can theoretically remove almost all ionic substances. At 25°C, the resistivity of the effluent reaches 18.2MΩ-cm. The quality of the ion-exchanged water mainly depends on the quality of the ion-exchange resin and the exchange efficiency of water and resin in the exchange column.
There are a lot of ion exchange resins on the market, and the quality is uneven, making it difficult for users to distinguish. Therefore, we suggest that users must pay attention to the brand of resin. chiwatec ultrapure water system adopts the highest quality ion exchange resin in the world, combined with Heal Force’s unique internal pressure structure design of the exchange column, to ensure full contact between the resin and water, significantly improve the exchange efficiency and maximize the processing capacity of the ion exchange column.
It should be noted here that the ion exchange method can effectively remove ions, but it cannot effectively remove most of the organic matter or microorganisms, and 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, which is the post-processing part we will discuss below.

3. Post-processing

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

The most stable water quality:

It is only the first step for the ultra-pure water system to produce high-quality ultra-pure water. For users, it is the most concerned issue for users to be able to maintain high water quality for 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 they have not made much improvement from their own aspects.
The chiwatec ultrapure water system is completely different. In addition to some common functions, it has the function of automatic cleaning at any time, standby for 2 hours and multiple time-off cycle sterilization and disinfection modes (liquid disinfection using hydrogen peroxide as a disinfectant) way, to better protect the operator and filter column, while ensuring the quality of ultrapure water), automatic shutdown when water is cut off, pure water/ultrapure water dual-flow design, etc., and a unique configuration to ensure stable water quality: two-stage ion exchange And each level is composed of two columns, which can reduce the organic load of the ultraviolet lamp, further improve the water quality and prolong the service life of the accessories, killing two birds with one stone. At the same time, the chiwatec ultra-pure water system has as many as 4 ultra-small, high-precision, 1/0.01 constant resistivity sensors, which can accurately monitor the conductivity or resistivity of each channel of pure water, automatically compensate for temperature, and have TOC measurement options , to achieve real-time detection of resistivity and TOC. Through these high-precision sensors, the ultrapure water system has the ability to automatically judge or prompt the failure of the pretreatment column, reverse osmosis membrane, primary purification column, multi-functional purification column, microfiltration, ultrafiltration, ultraviolet lamp, etc., to ensure that the machine It is in the best operating condition to ensure the quality of produced 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

EDI ultrapure water treatment

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