From an academic point of view, pure water, also known as high-purity water, refers to the chemical purity of water, which is mainly used in biology, chemical industry, metallurgy, aerospace, power and other fields, but its water purity requirements are quite high, so the general application of the most common or the electronics industry. For example, the pure water used in the power system, the requirements of the impurity content of low to "micrograms / liter" level. In the production of pure water, water quality standards for the indicators should be based on electronic (microelectronics) components (or materials) of the production process (such as the general view that the size of the particulate matter caused by the destruction of the circuit performance of the line width of 1/5-1/10), but due to the complexity of microelectronics technology and product quality of the factors affecting the product quality, so far there is no one by the process of experimentation applicable to a certain circuit Production of a complete water quality standards. However, in recent years, electronic grade water standards have been revised, and many breakthroughs in the field of high-purity water analysis and development, the continuous application of new instruments and new analytical methods have created conditions for the development of water production process.

Pure water

Introduction: pure water, also known as deionized water, is to meet the health standards for domestic drinking water as raw water, through the electrodialyzer method, ion exchanger method, reverse osmosis, distillation and other appropriate processing methods, produced in sealed containers, and does not contain any additives, colorless and transparent, can be directly consumed, can also be referred to as the pure substance (in the chemical). It is also known as pure (chemically) water, which is used more in experiments, and is also known as distilled water because it is made by distillation and other methods. Space water sold on the market, distilled water are pure water; but pure water or drink less for the better, because there is not too much inside the minerals that the human body needs. Pure water is not easy to conduct electricity, is an insulator. Lead-acid battery replenishment to use pure water.

Basic introduction:

1. water refers to the impurity-free H2O. from an academic point of view, pure water, also known as high-purity water, refers to the chemical purity of the water is very high, and its main applications in the field of biology, chemical chemical industry, metallurgy, aerospace, power and other fields, but the purity of the water quality requirements are quite high, so the general application of the most common or the electronics industry. For example, the pure water used in the electric power system, the requirements of the impurity content of low to "micrograms / liter" level. In the production of pure water, water quality standards for the indicators should be based on electronic (microelectronics) components (or materials) of the production process (such as the general view that the size of the particulate matter caused by the destruction of the circuit performance of the line width of 1/5-1/10), but due to the complexity of microelectronics technology and product quality of the factors affecting the product quality, so far there is no one by the process of experimentation applicable to a certain circuit Production of a complete water quality standards. With the continuous revision of electronic grade water standards, but also many breakthroughs in the field of high-purity water analysis and development, new instruments and new analytical methods are constantly applied to create the conditions for the development of pure water process.

2. Pure water also refers to the water filtered through the water purifier (RO machine).

3. Pure water refers to water salts (mainly strong electrolytes dissolved in water) removed or reduced to a certain degree of water purification equipment. 1.0-10.0μS/cm, resistivity (25 ℃) 0.1-1.0 * 106cm salt content of 1-5mg / L.

Related indexes:

In China's barrel-filled drinking water market, there are mainly pure water Mineral water, spring water, spring water and natural water, mineral water, etc., due to mineral water, spring water, etc. by resource constraints, and pure water is the use of tap water after a certain production process for production, so the people on the market drink the most or pure water, the quality of pure water and the people's life has a close relationship. For this reason, the State Bureau of Quality and Technical Supervision in April 1998 issued GB173233-1998 "bottled drinking water" and GB17324-1998 "bottled drinking water health standards". In these two standards,*** there are 4 sensory indicators, 4 physical and chemical indicators, 11 health indicators.

(A) sensory indicators

Sensory indicators include color, turbidity, odor, visible to the naked eye. These indicators are the most basic indicators of quality control of pure water, the development of standard values with reference to drinking water (i.e., tap water) standards, and most manufacturers of pure water production is the source of tap water, and through the process of coarse filtration, fine filtration and deionization and purification, so the general pure water can meet the national standards required values.

(B) physical and chemical indicators

Physical and chemical indicators of the more important is the conductivity and potassium permanganate consumption. Conductivity is a characteristic indicator of pure water, reflecting the degree of purity of pure water and production process control. As drinking water does not go through the process of deionization and purification, this indicator is not examined. For pure water, "purity" is the most basic requirement, metal elements and microorganisms are too high, will lead to high conductivity. Therefore, the smaller the conductivity, the purer the water.

Potassium permanganate consumption refers to the number of milligrams of oxygen consumed by the oxidation of reducing substances by potassium permanganate in 1L of water under certain conditions, and it mainly examines the content of organic matter in water, especially the content of chlorides.GB17323-1998 《Bottled Purified Water for Drinking》specifies that the consumption of potassium permanganate in drinking water (in terms of O2) shall not be more than 1.0 mg/L. 1.0mg/L. If the consumption of potassium permanganate is high, there may be microorganisms in the water exceeding the standard, or some manufacturers may increase the amount of disinfectant ClO2 to prevent microorganisms from exceeding the standard, thus producing some new organic halogenated substances, in which case the free chlorine will also exceed the standard.

(C) health indicators

Health indicators include metal elements, organic matter and microorganisms and other categories.

1. Metal indicators

Metal indicators in the standard of lead, arsenic, copper content, lead, arsenic requirements shall not exceed 0.1mg / L, which mainly comes from the environment affected by human activities, including soil, river pollution and so on. Lead, arsenic for toxic and harmful elements, lead can enter the human body by the respiratory tract or digestive tract and accumulate in the body, when the blood lead content of 0.6 ~ 0.8mg / L will damage the internal organs, and arsenic compounds will cause poisoning, therefore, their content should be the smaller the better, while the copper in the standard shall not exceed 1.0mg / L, although the copper is not a harmful element, but it is not a more or less good substance. For pure water, it is a measure of its purity of one of the signs.

2. Organic indicators

Organic indicators in the national standard is mainly reflected in the content of trichloromethane (chloroform) and carbon tetrachloride regulations. As the barrel of pure water quality problems are mainly concentrated in the microbiological test exceeds the standard, in order to solve this problem, many manufacturers are not from the production process, quality management, but only by increasing the amount of disinfectant to try to solve the problem of microbial contamination of pure water, commonly used disinfectants are chlorine-containing disinfectants such as chlorine dioxide and other disinfectants. Barrels of pure water due to chlorination disinfection can produce some new organic halogenated substances, the main components are trichloromethane (chloroform) and carbon tetrachloride and a small amount of chloromethane, a bromine dichloromethane, dibromo chloromethane, and bromoform, etc., collectively referred to as halogenated alkanes. The content of halothane in chlorinated drinking water and tap water is generally higher than that in source water. Among them, the content of trichloromethane and carbon tetrachloride is higher, which is harmful to the human body, and if you drink purified water with excessive chloroform and carbon tetrachloride for a long period of time, it will lead to liver poisoning or even cancer in serious cases. In order to protect the health of consumers, in the national standard GB17324-1998 clearly stipulates that: the content of trichloromethane and carbon tetrachloride in drinking water shall not exceed 0.02mg/L, 0.001mg/L.

3. Microbiological indicators

Microbiological indicators in the national standard stipulated in the total number of colonies, coliforms, pathogenic bacteria, Coliforms, pathogenic bacteria and molds, yeast 4. From the pure water testing in recent years, microbiological indicators are more likely to exceed one of the indicators. This is due to microbial contamination in the pure water in the production and processing, transportation and sales process and other links. In the production and processing, workers do not pay attention to personal hygiene, recycling bottle cleaning, disinfection is not strict, and even some manufacturers in order to reduce the cost of recycling bottle caps for re-use, due to the deformation of the recycled bottle caps, resulting in the mouth of the bottle is not sealed may cause microbial contamination. Microorganisms exceeding the standard reflects the degree of water contamination. Among them, E. coli reaches a certain target, will cause human diarrhea. Pathogenic bacteria include Salmonella, Shigella, Staphylococcus aureus and Streptococcus B. The most common microorganisms are Salmonella, Shigella and Streptococcus B. Salmonella, Shigella contaminated water will cause acute intestinal infectious diseases, diarrhea and fever and other symptoms; Staphylococcus aureus produces enterotoxins can cause human poisoning, acute gastrointestinal symptoms, and even life-threatening; Streptococcus B is the main pathogen causing human septic inflammation; molds and yeasts are commonly found in the natural world, molds growing in the food in the reproduction process of the food sucked In the process of reproduction, molds grow in food and absorb the nutrients of food to reduce the nutritional value of food, and emit odors, affecting the sensory of food, especially the toxins produced during the growth of molds can cause chronic poisoning of the human body, and in severe cases, can lead to cancer.

(d) the national standard health indicators there is an important indicator of nitrite content. Nitrite mainly from water sources near the soil in the nitrate, saline, large amounts of nitrate fertilizer and molybdenum deficient soil in the nitrate content is higher. In the national standard nitrite shall not exceed 0.002mg / L.