Demineralization is the process of eliminating mineral salts in water by using the ion exchange process. Demineralised Water is the water which is free of dissolved minerals.
Demineralization is also called deionization and is used to remove the salts and minerals available in the water to make it drinkable and soft. Mineral water consists of certain limited quantity of salts, calcium, magnesium, sodium etc but the quantity is inadequate. As a result of which such water is hard to drink so it is preferable by many to make it free from such minerals or salts. Though many people and medicals entities claim mineral water to contain adequate minerals so that it prevents much of water borne disease.
Demineralization is performed with help of ION Exchange, RO, distillation and electro dialysis processes. RO and electro dialysis are performed to remove the dissolved solids with the help of membrane process where as Ion exchange is softening process which is mostly used to remove the hard minerals such as calcium, magnesium from the water or waste water. In this process, Hydrogen (H+) and Hydroxide (OH-) are used to replace the negative and positive ions. Negatively charged ions are called anions and positively charged ions are called cations.
Cations include the calcium, magnesium, sodium which is treated with acid and replenishes with H+ ions. Whereas Anions denotes chloride, sulfate, nitrate and bicarbonate etc and replenished through OH- ions. It is assumed that the treated water is already filtered but is hard enough to drink.
Demineralized Water also known as Deionized Water, i,e. the water that has its mineral ions removed. Mineral ions are commonly present in Water. Deionization is a process which uses ion exchange resins for swapping off the mineral salts in Water with Water forming H+ and OH- ions. Deionized water is as pure as distilled Water, and this process is quick and free of scale build-ups.