Introduction of ultra pure water for laboratory
Overview of ultrapure water for laboratory use
Most of the ultra-pure water used in the laboratory has high requirements on water quality. According to different applications, it can be divided into three levels of water: first-level water, resistance requirements greater than 10MΩ.cm (conductivity lower than 0.1us / cm), mainly used For demanding analytical tests, including those required for particles. Such as high-pressure liquid chromatography analysis of water. The first-grade water is usually prepared by distilling or reverse-osmosis and ion-exchange mixed bed treatment through quartz equipment, and then filtering through a 0.2 μm microporous filter membrane. For secondary water, the resistance must be greater than 10MΩ (conductivity lower than 0.1us / cm), which is mainly used for inorganic trace analysis and other tests, such as water for atomic absorption spectrometry. The secondary water can be prepared by multiple distillation or reverse osmosis and ion exchange methods. Tertiary water, tertiary water is used for general chemical analysis tests. The tertiary water can be prepared by distillation or ion exchange.
Use EDI module as post processing
Electric deionized ultrapure water treatment equipment using reverse osmosis host plus EDI
Electric deionized ultrapure water treatment equipment
Common methods for preparing laboratory water
The most commonly used type of pure water in the laboratory, although the equipment is cheap, is extremely energy and water consuming and slow, and the application will gradually decrease. Distilled water can remove most of the pollutants in tap water, but volatile impurities such as carbon dioxide, ammonia, silica, and some organics cannot be removed. Fresh distilled water is sterile, but bacteria can easily multiply after storage. In addition, the storage container is also very particular. If it is a non-inert substance, ions and plastic molding materials will precipitate and cause secondary pollution.
2. Deionized water:
The use of ion exchange resins to remove anions and cations in water is a traditional process used to make pure water for a long time. After treatment, ultrapure water with a certain purity can be obtained, but soluble organic matter still exists in the water. It can contaminate the ion exchange column and reduce its efficiency. Deionized water can easily cause bacteria to multiply after storage.
3. Reverse water seepage:
The generation principle is that water molecules become pure water through a reverse osmosis membrane under the action of pressure, and impurities in the water are trapped and discharged by the reverse osmosis membrane. Reverse osmosis water overcomes many of the shortcomings of distilled water and deionized water. The use of reverse osmosis technology can effectively remove dissolved salts, colloids, bacteria, viruses, bacterial endotoxins and most organic impurities in water.
4, ultra pure water:
The standard is 18.2 MΩ-cm. The latest technology for the production of ultrapure water often uses reverse osmosis plus ion exchange mixed bed or reverse osmosis plus electric deionization (EDI), which is more economical and environmentally friendly than the former.