| Deionized water has become very important | | | | calcium (Ca++) and magnesium (Mg++) ions. But |
| these days that its production is highly anticipated | | | | for overall removal of ions in water, negative and |
| in many industries. It is also called DI water or | | | | positive ions should be removed. In more |
| demineralized water and is often compared to | | | | sophisticated deionization systems, it passes |
| distilled water, which is essentially similar to it. | | | | through a resin bed that contains hydrogen ions |
| Manufacturers of medicines, chemicals, food, | | | | (H+). The hydrogen ions replace all the positive |
| cosmetics, and car batteries use this type of | | | | ions in the water. The resulting water would still |
| water. Also, many rinsing and cleaning chemicals | | | | contain negative ions which are replaced by |
| contain water that has undergone deionization. | | | | hydroxyl ions (OH-) in the second resin bed. The |
| Deionization of Water | | | | water that comes out is extremely pure that is |
| Water never comes pure in nature and this is | | | | devoid of ions or minerals. |
| why companies need to purify it to a usable | | | | Relevance of DI Water |
| extent. There are various treatment methods to | | | | Water for general home use need not undergo |
| ensure its pureness and potability. Water coming | | | | deionization. Sanitary drinking water may contain |
| from the natural sources contains many impurities | | | | some ions but deionization is not a hygienic |
| (minerals, organic compounds, microorganisms, | | | | requirement. However, many people prefer |
| and microscopic organic matter). These impurities | | | | deionized or distilled water not because of the |
| should be removed and their concentration must | | | | absence of ions but because the process it |
| be reduced to a negligible or harmless extent. For | | | | undergoes ensures its safety. DI water undergoes |
| this to be possible, it must undergo several | | | | such a stringent treatment process that it |
| treatment steps. | | | | becomes ultra pure and very safe for drinking. |
| The liquid usually undergoes filtration and is passed | | | | The production of water devoid of ions, however, |
| through layers of sand to remove sediments. | | | | is quite relevant in many industries. As mentioned |
| Activated carbon then filters out colloidal particles. | | | | in the first paragraph, demineralized water is |
| The resulting water may still be unsafe due to | | | | important part in the production of food, |
| bacteria and substances whose molecules are | | | | medicines, and cosmetic products. In laboratories, |
| small enough to pass through porous filters. There | | | | pure water is needed to rinse laboratory |
| are many ways to remove smaller molecules and | | | | glassware. Autoclave water used to disinfect |
| bacteria. Reverse osmosis is the next process | | | | medical instruments is also essentially DI water. |
| employed to remove organic molecules. It may | | | | This kind of water is used in specialized |
| remove bacteria and microorganisms but other | | | | applications wherein tap water is inappropriate. |
| water companies employ ultraviolet treatment. | | | | Plain mineral water contains considerable |
| The resulting water may be potable but still has | | | | concentration of ions that affects the quality of |
| considerable ion content. Ions result from the | | | | resulting products in industries. Deionized or |
| dissolution of mineral salts in water. These salts | | | | demineralized water is also important in industrial |
| occur in the natural environment and because ions | | | | cleaning because water with enough mineral |
| are very small they are able to pass through | | | | content can cause scales in equipment that either |
| filters and some remain even after RO process. | | | | lower the efficiency or ruin the equipment after a |
| There are two basic ways to remove these ions | | | | time. If you heard that car wash companies use |
| namely, distillation and deionization. Deionization is | | | | DI water as the final rinse, that's because you |
| employed by passing the liquid through ion | | | | want to see your car surface and windows |
| exchange resin beds. | | | | spotless after the cleanup. Without ions in the |
| There are home water softeners with resins | | | | liquid, it cleans efficiently without leaving any scales |
| containing sodium ion (Na+), which replaces | | | | or spots. |