Demineralized water in detail: definition, extraction, and areas of application
Compared to tap, rain, or filter water, demineralized water should not be drunk in the long term. The reason: Distilled water is exclusively H20, which contains neither salts nor minerals such as lime or ions. If you were to use ultrapure water for hydration in the long term, numerous important substances such as sulfur or calcium would be flushed out of the body. The entire mineral and electrolyte balance is brought out of balance by pure water. Nevertheless, demineralized water is important for other areas of application:
- Household: Distilled water is used in many households, although not as a thirst quencher. The water has an excellent cleaning value due to its slightly acidic properties and is most commonly used for ironing. Since it contains no lime, there are no deposits on trousers and shirts.
- Solar systems: Solar systems are also sensitive to limescale deposits. These can drastically reduce the performance of the system and therefore ultrapure water is recommended for cleaning.
- Solvents: In industry, ultrapure water is used as a solvent because it is very aggressive when completely desalinated.
- Coolant: Another area of application for demineralized water is cooling lines, for example in refrigerators. Since it contains no minerals, no deposits form, which preserves the longevity and function of the cooling circuit.
- Battery water: Distilled water is used together with sulfuric acid as battery water. If the water used contained minerals or ions, improper discharge and problems would result over time. These would wear out the car battery more quickly and lead to many a dangerous situation if it short-circuits while driving.
The extraction of demineralized water
Demineralized water is obtained either via ion exchange or reverses osmosis. After this procedure, the water is desalinated to really filter all foreign matter out of it. Due to the difficult procedure, demineralized water is offered in bottles for private consumers.
- So-called ion exchangers are used for ion exchange. These are substances that filter the ions out of the water. This leads to demineralized water. These substances are either naturally occurring, zeolite, or artificially produced, polystyrene. They bind the ions to themselves when they come into contact with water. They are located in special filters through which water is passed. As a result, you get ultrapure water.
- Reverse osmosis uses a mixture of high-pressure water and various materials to filter the water. A membrane made of polyester, polysulfone, polyamide, and a grid is used. The plastics act as a filter while the grid creates movement as the water is shot through the membrane at high pressure. This is connected to the water cycle in a container and now filters the pollutants, minerals, metals, and other substances from the water. Depending on the need, the water is cleaned several times, even the wastewater. Reverse osmosis is significantly more effective than ion exchange.
- Desalination: Water that no longer contains any salts is called deionized water. Fully desalinated water is obtained using one of the two techniques already mentioned. The goal is particularly pure water that should no longer be drunk by children between 0 and 6 years due to the lack of salts. This could have harmful effects on health.