What is the difference between pure water and ultra-pure water?

Pure water, also known as purified water, refers to the raw water that conforms to the sanitary standards for drinking water, is produced through electrodialysis, ion exchanger, reverse osmosis, distillation and other appropriate processing methods, to get water that can be drunk directly, without any additives, colorless and transparent, and is sealed in container. Strong electrolyte and weak electrolytes (SiO2, CO2, etc.) in raw water are removed or reduced to a certain level. Conductivity of pure water is commonly 1.0-0.1 μs/cm, resistivity (at 25 ℃) is 1.0-10.0 M Ω * cm, salt content is less than 1 mg/L.

Ultra-pure water is based on pure water to further remove conductive medium in water almost completely, and remove the non-dissociated colloidal substances, gases and organic matter in the water to a very low degree of water. Resistivity of ultra-pure water is more than 18 M Ω * cm or close to 18.25 M Ω * cm limit value. Ultrapure water is general level of the process is difficult to achieve, can be in microfiltration, ultrafiltration, reverse osmosis, EDI technology, two or more of the ion exchange technology, through the reasonable technological design, equipment selection, can produce ultrapure water, can be up to 18.20 M resistivity Ω * cm .

Difference between pure water and ultrapure water exists in many ways, specific summarized as follows:

A) different conductivity, water conductivity between 2-10 us/cm, ultrapure water conductivity is 0.056 us/cm;

B) has different manufacturing difficulties. At present, the pure water used in the market is basically obtained by reverse osmosis, distillation and other methods, while ultra-pure water is obtained by a series of complex purification technologies such as photooxidation technology, fine treatment and polishing treatment on the basis of pure water.

C) heavy metal, bacteria, particle number and other indicators are also very different. The pure water impurity content is PPM level, while the ultrapure water is PPB level. 

D) the fields used are also different;

E) also has different requirements on the material of the conveying pipeline. Ultrapure water has more strict requirements on the material of the conveying pipeline than ultrapure water.

What are the main applications of pure water and ultrapure water?

Application of pure water: the final cleaning of laboratory utensils buffer solution, chemical reagent preparation water microbial culture medium preparation water hydrogen generator, indoor humidifier, high-pressure disinfection pot pure water for human or laboratory animals drinking water.

Application of ultrapure water are: (1) fine animal and plant cell culture with water (2) the various biochemical apparatus for medical use, analyzer, hemodialysis meter (3) analytical reagent and drug allocation diluted with water (4) physiology, pathology, toxicological experiment in the use of water (5) of pharmaceutical preparation in hospital, medical and lab center with purified water and water of high pure water 6 atomic absorption spectrometry 7) test-tube baby water all kinds of high performance liquid chromatography (HPLC), ion chromatography pet-name ruby various laboratory water and medicine in the use of water. At present, the most stable and convenient method to prepare pure water and ultra-pure water is through the pure water/ultra-pure water system.