Pure water system generally refers to a type of device that achieves the purpose of purified water through various water treatment processes and water quality monitoring systems. Common impurities in natural water include soluble inorganics, organic matter, particulate matter, microorganisms, soluble gases, etc. In general, the water purification process can be roughly divided into four steps, pretreatment (primary purification), reverse osmosis (production of pure water), ion exchange (production of 18.2MΩ.cm ultrapure water) and terminal treatment (ultrapure water that meets special requirements).
1. Pretreatment
Pretreatment refers to the preliminary treatment of raw water (such as tap water, groundwater, surface water, etc.), the purpose is to remove most of the suspended solids, colloids, organic matter, microorganisms and some dissolved impurities in the water. It mainly includes large particulate matter, residual chlorine and calcium ions and magnesium ions. In order to solve this problem, precision filters, activated carbon adsorption filters and softening resins are designed to remove large particulate matter, residual chlorine and calcium ions and magnesium ions in the water to achieve the best pretreatment effect.
2. Reverse osmosis
Reverse osmosis is the use of a high-pressure pump to provide a high concentration of solutions with a large pressure difference in osmotic pressure, water molecules will be forced to pass through the semi-permeable membrane to the side of the lower concentration, reverse osmosis can filter out 90%-99% of the vast majority of pollutants including inorganic ions, because of its excellent purification efficiency, reverse osmosis is a very effective technology for water purification systems, because reverse osmosis can remove most of the dirt.
3. Ion exchange
Ion exchange is the exchange of positive ions in water and H ions in ion exchange resin, and the exchange of negative ions in water with OH- ions on ion exchange resins, so as to achieve the purpose of purifying water. Ion exchange can theoretically remove almost all ionic species, and at 25°C, the effluent resistivity reaches 18.2 MΩ. cm。 The quality of the effluent through ion exchange mainly depends on the quality of the ion exchange resin and the exchange efficiency of the water and resin in the exchange column.
4. Terminal Processing
According to the special requirements of customers, ultra-low organic, sterile, and non-pyrogenic ultrapure water is produced. There are a variety of treatment methods for different requirements, such as ultrafiltration filtration for heat removal, dual-wavelength ultraviolet oxidation for reducing total organic carbon (TOC) in water, microfiltration for bacteria removal, etc.