The grade allocation of pure water is based on the conductivity and resistivity of the water quality as the classification criteria. The grades of water required in the laboratory are distilled water, deionized water, reverse osmosis pure water, and ultrapure water.

 

Distilled water: The treated raw water is subjected to high-temperature treatment to change the water quality from liquid to gas, and then cooled and liquefied to produce distilled water. The distillation method can produce most of the pollutants in the water (ammonia, silica, carbon dioxide, etc.), which is a relatively traditional method for producing pure water.

 

Deionized water: There is a standard deionized water treatment process flow (raw water → multi-media filter → activated carbon filter → precision filter → cation bed → anion bed → mixed bed → rear security filter → water point), which uses the principle of exchange resin to remove anions and cations from water to produce pure water.

 

Reverse osmosis pure water: The use of reverse osmosis water treatment technology can remove viruses, bacterial endotoxins, colloids, bacteria, organic matter, etc. contained in water, overcoming the problems of high energy consumption, waste of raw water resources, slow effluent, and soluble organic matter in deionized water technology of distillation method.

 

Ultra pure water technology: By using ultra pure water technology, water with a resistivity greater than 18.2M Ω· cm (25 ° C) can be produced, which can remove not only water molecules but also the mineral and trace elements required by the human body.

 

The water quality produced by different water treatment technologies varies, such as the different indicators of pure water used in different experiments. Therefore, it is ultimately necessary to customize the pure water treatment process according to the water requirements of the laboratory.