Ultrapure Water Equipment Design Guide Chapter 1 Introduction
Table of Contents
1.1: Definition of pure water
1.2: The use of pure water
1.3: Classification of pure water
1.1: Definition of pure water
Pure water is an inorganic compound with the chemical formula H2O, a liquid with a certain structure. In liquid water, the molecules of water do not exist as a single molecule, but several molecules are associated with hydrogen bonds to form clusters of water molecules (H2O), so the orientation and movement of water molecules will be significantly affected by other surrounding water molecules.
From an academic point of view, pure water refers to water with extremely high chemical purity, which is mainly used in biomedicine, food and catering, chemical industry, precision manufacturing, metallurgical power, aerospace, electronic semiconductors and other fields.
1.2: The use of pure water
Pure water refers to water that has been treated to remove impurities, minerals, and organic matter, and has a purity of up to 99More than 9%, pure water has a wide range of uses in life and industry.
Pure water is very versatile in life. We need drinking water every day, and pure water is one of the safest and healthiest drinking waters. Pure water removes most of the impurities and minerals, which can effectively protect our health. In addition, pure water can also be used for cooking, washing face, bathing, etc. In cooking, the use of pure water can make food more delicious without affecting the taste of the food. In washing your face and bathing, pure water can effectively clean** and make **healthier**.
Pure water also has a wide range of uses in industry. Pure water is used in many industrial processes, such as electronics, semiconductors, pharmaceuticals, chemicals, and other industries. In the electronics and semiconductor industry, pure water is used to clean and rinse electronic components and semiconductor chips. In the pharmaceutical and chemical industries, pure water is used as a solvent and reaction mass for pharmaceutical and chemical reactions. In addition, pure water can also be used to make paper, printing, dyeing, cooling, etc.
Pure water can also be used for environmental protection and scientific research. In terms of environmental protection, pure water can be used to purify sewage and wastewater and reduce water pollution. In terms of scientific research, pure water can be used for chemical analysis and biological experiments in the laboratory to ensure the accuracy of experimental results.
Pure water has a wide range of uses in life and industry. It can not only protect our physical health, but also promote the development of industrial production and scientific research.
1.3: Classification of pure water
There is no complete classification of pure water in a clear sense at home and abroad, and the classification of pure water is roughly as follows according to the different implementation standards.
1.3.1. Purified water
Implement GB 17324-2003 hygienic standard for bottled (barrel) drinking water.
In addition to the specific requirements of physical and chemical indicators such as conductivity of 10 s cm (25), the pure water standard also has specific index requirements in four sensory requirements (color, turbidity, odor and taste, visible to the naked eye) and four microbial indicators (total number of colonies, number of coliforms, mold and yeast, pathogenic bacteria), which is also the biggest difference between domestic pure water and general industrial pure water.
1.3.2 (General) Industrial Pure Water
Industrial pure water standards can vary according to different industries and specific uses, and generally include the following indicators:
1) Conductivity: The conductivity of industrial pure water should reach a certain low value, which is generally required to be between 5-20 s cm.
2) Total dissolved solids (TDS): The total dissolved solids content of industrial pure water should be as low as possible, generally less than 100 mg L.
3) Specific volume per unit volume: The specific volume of industrial pure water should be small, and the general requirement is less than 11 ml/g。
4) pH value: The pH value of industrial pure water should be close to (7), and the general requirement is between 6-8.
5) Total number of bacteria: The total number of bacteria in industrial pure water should be controlled within a certain range, and it is generally required to be less than 100 cfu ml.
Note: Industrial pure water may also need to meet other specific requirements in specific applications, such as the removal of pathogenic microorganisms, the removal of heavy metals and organic matter, etc. It should be noted that the requirements of different countries and regions for industrial pure water standards may be slightly different, and enterprises should refer to the corresponding regulations and standards when selecting and using industrial pure water.
1.3.3. Electronic grade water (high purity water).
Execute GB T 114461-2013 Electronic grade water quality standard.
Electronic grade water is defined as high-purity water used in electronic and semiconductor processes.
China's electronic grade water standard divides electronic grade water into four levels: grade, grade, grade, grade, the standard is formulated with reference to the American ASTM electronic grade standard.
The main basis for the indicators specified in the water quality standards for electronic grade water is as follows:1Water quality requirements for microelectronic processes;2.The level of water production technology;3.The state of the detection technology.
1.3.4. Ultrapure water
There is no clear water quality standard for ultrapure water in China, and it generally refers to water with a resistivity of 18 m * cm (25). In addition to water molecules, there are almost no impurities, no bacteria, viruses, chlorinated dioxins and other organic matter, and of course, there are no minerals and trace elements required by the human body, that is, water that almost removes all atoms except oxygen and hydrogen.
Ultrapure water in a broad sense generally refers to pure water with a resistivity of 10m*cm (25), and the corresponding technical indicators conform to the electronic grade water grade and above.
At present, the domestic electronic semiconductor industry generally implements the electronic grade water EW- standard, or the more stringent ASTM D5127-2013 (2018) Type E-12/1.3. Ultrapure water quality standards.
1.3.5 (medical) purified water
Implement the relevant provisions of the Chinese Pharmacopoeia-2020 Edition, and its main physicochemical and technical indicators are as follows: 1) **Purified water is pharmaceutical water prepared by distillation, ion exchange, reverse osmosis or other appropriate methods, without any additives.
2) Shape: colorless clear liquid, odorless.
3) pH: meet the requirements.
4) Nitrate: 0000006%
5) Nitrite: 0000002%
6) Ammonia: 000003%
7) Conductivity: 43μs/cm（20℃）；5.1μs/cm（25℃）
8) Total organic carbon (TOC): 05mg/l
9) Easy oxides: meet the requirements (choose any one with total organic carbon).
10) Non-volatiles: 1mg 100ml
11) Heavy metals: 000001%
12) Microbial limit: the total number of aerobic bacteria is 100cfu ml
1.3.6. Laboratory water
Implement GB T 6682-2008 Analytical Laboratory Water Specifications and Test Methods Standard.
Summary: The above is the basic classification of common pure water in daily production and life, among which there are clear national standards for pure water, electronic grade water, purified water and laboratory water, while general industrial pure water and ultrapure water belong to the conventional name, and its specific technical indicators and standards are not uniform, in the selection and use, we should refer to the corresponding regulations and standards, and negotiate to establish specific standards to avoid related problems and risks.
In terms of conductivity, the cleanliness of common pure water is ranked as follows: ultrapure water, electronic grade water, laboratory water, purified water, purified water, and general industrial water.
Note: Conductivity ec( S cm) * resistivity rt (m * cm) = 1.