About Pure Water and Ultrapure Water

The Properties of Water

Strong Dissolving Power

Even colorless, transparent water contains a variety of components. For example, if a 50 m swimming pool were filled with tap water, it would contain the equivalent of several metal drums full of impurities.

In other words, water has strong dissolving power. With pure or ultrapure water, from which impurities have been removed, that power becomes even stronger.

Usage Scenarios for Pure and Ultrapure Water, Drawing on the Properties of Water

Remove Pollutants and Extract Components

In pure water containing almost no impurities, the water properties are manifested even more clearly and its dissolving power becomes even stronger.

There are many situations that take advantage of these characteristics.

Prevent Adhesion of Impurities on Equipment and Functional Degradation

Continued use of a boiler or humidifier with water containing a high volume of impurities leads to a buildup of impurities (such as scale) inside the boiler or humidifier. This causes pipe blockages and adversely affects heat transfer, resulting in decreased equipment functionality.

Pure water is used to prevent decreased functionality caused by scale formation.

Pure water is also used for the cleaning of equipment and in experiments, so that impurities do not interfere with the effects of the cleaning agent (such as surfactant) or hinder the experiment.

About Pure/Ultrapure Water

What are Ultrapure Water and Pure Water?

Ultrapure water refers to high-purity water where river water or water for industrial use has been made as close as possible to pure H₂O by combining water purification component technologies. The water is processed to an ultra-high level of purity by removing not only solid substances and salts, but also gas dissolved in the water. Organo’s industry-leading analysis technology is also essential in the manufacture of ultrapure water.

Pure water refers to highly pure water with few impurities. It indicates a state in which almost all salts and organic matter have been removed, and depending on the method employed to remove impurities, the water is referred to as desalinated water (water in which the salts are removed using ion exchange resins or other agents), RO (reverse osmosis) water (water filtered through a reverse osmosis membrane), or distilled water (water derived from steam that has been cooled and condensed back into liquid).

In fact, there is no precise definition for pure water. Typically, it refers to water with an electric resistivity ratio of 0.1 to 1.5 MΩcm. The fewer impurities water has, the higher its electric resistivity ratio, and the lower its conductivity.

Ultrapure water is water that has been made as close as possible to pure H₂O. The electric resistivity ratio of theoretically pure water is 18.24 MΩcm, and ultrapure water has been made as close as possible to this level. In fact, there is also no precise definition for ultrapure water.

What is Ultrapure Water Used For?

・Cleaning the surfaces of semiconductor wafers and liquid crystal panels, which must have no minute foreign particles

・In steam generators for the power generating turbines needed for the stable operation of power plants

・As injection water for the healthcare and pharmaceutical industries, where safety is always a top priority

・As blank water for microanalysis, which directly affects analysis results

Ultrapure water is used in a wide range of fields.

What is Pure Water Used For?

・To dilute soft drinks before bottling to remove the unpleasant taste

・For precision cleaning, to prevent water marks

・As dilution water to stabilize quality, such as used in pharmaceuticals

・For boilers and humidifiers, to prevent scale formation

Pure Water Around You

Pure Water Technology Around You

Pure water and ultrapure water are most commonly used in producing semiconductors and liquid crystal panels, essential components of high-tech equipment. This includes the semiconductor wafers and liquid crystal panels found in mobile phones, digital cameras, and LCD and organic EL TVs. Even nanoparticles are unacceptable in semiconductor wafers and liquid crystal panels. Pure water and ultrapure water are used to remove these minute particles, and in producing food and drinking water, as well as in the manufacture of pharmaceuticals. Pure water with no impurities or pyrogens is also used in making eye drops.

Water for Cleaning

Water for cleaning is as familiar to us as drinking water. We can easily think of numerous ways we use water in daily life—washing our hands and faces, doing laundry, and mopping floors are just a few.

Cleaning is also performed in various situations in industry. Examples include the removal of hazardous substances in the food industry, surface cleaning prior to plating or painting, removal of malodorous components, and improvement of the texture of textile products.

The surprising connection between wine glasses and pure water

There are many wine enthusiasts in Japan as well. Wine glasses, which play an important role in the enjoyment of wine, come in various shapes that enhance the wine’s aroma or taste. However, it takes a lot of effort to properly care for wine glasses. If you don’t take proper care, you can ruin the experience.

The biggest enemy of the wine glass is water scale. If you wash a glass and leave it to dry naturally, before you know it, scale has formed and made the glass cloudy.

Water scale is caused by the impurities in tap water. Though most tap water in Japan is soft, it still contains Ca²⁺ (calcium ions) and Mg²⁺ (magnesium ions).
These become calcium carbonate and magnesium silicate, and once they have dried, they are deposited in white clumps and become water scale.

Both Ca²⁺ and Mg²⁺ are types of metal ions, so once they are caked on they are very difficult to remove. It’s good to wipe the glass dry with a special cloth while it’s still damp, but doing it every day is a chore! For wine enthusiasts, we recommend cleaning with pure water.

Water that Draws Out the Power of Materials

Pure water with no impurities has superior dissolving power.

Take green tea, for example. Pure water is used during the extraction process in the production of green tea sold in plastic bottles. Every last drop of the tea’s active ingredients can be extracted, unhampered by impurities, resulting in a consistently high-quality product. Pure water is also one type of water used in the production of soft drinks, beer, and sake, as it does not affect the flavor. However, in some cases it is not suitable, as it can eliminate too many components such as bitterness or other off-flavors. Therefore, we recommend selecting the type of water ideal for the particular application.