WHAT IS DEMINERALIZATION?

The process of expelling or removing all the minerals that are found in natural water is known as “Demineraatlizion”. When the water is to be used for certain chemical processes, demineralization is done, so it becomes essential to remove the minerals that may interfere with the chemicals.

Is demineralized water same as purified water?

DM water or demineralized water is just purified water but purified water is highly purified as compared to DM water. It is used for laboratory applications for industrial as well as scientific purposes. Ion exchange resins play an important role in this demi water process.

In natural or raw water following ions are present:

Cations                                             Anions

Calcium (Ca2+)                               Chloride (Cl-)

Magnesium (Mg2+)                       Bicarbonate (HCO3-)

Sodium (Na+)                                 Nitrate (NO3-)

Potassium (K+)                              Carbonate (CO32-)

3 ways of water purification and treatment by ion exchange technology

1. 1. For water softening by Base Exchange, cation-exchange resins can be used. 
2. 2. For the purpose of organic scavenging or removal of nitrate, anion exchange resins are used.
3. 3. Deionization: A process in which all ionic impurities that are in natural water are expelled virtually. In this processcation-exchange and anion-exchange resins are used in combination. The water thus obtained is called soft water as the hardness present in this water is eradicated by the demineralization method.

In the demineralization process, the natural water is “softened” expelling the minerals and replacing it with salts. The cosmetic products are made of demineralized water.

For removing impurities, purified water is filtered mechanically. This purified water is then perfect to use and is made using DM water. For the preparation of purified water, demineralized water is made to pass through a semi-permeable membrane known as RO
(Reverse Osmosis) membrane and UV light (ultra violet expels microbes). The soluble impurities are removed through Reverse Osmosis(pore size 0.0003µ)

 In the pharmaceutical industry, purified water is used. This water is used as a raw material, component and solvent. This is used in processing and manufacturing of pharmaceutical products, active pharmaceutical ingredients and other pharmaceutical reagents.

TheDM water and purified water have to pass quality tests and for that they have their own specifications. 

• Demineralized water should only pass the two tests

1. 1. Hardness test.
2. 2. pH test.

• Whereas purified water need to undergo various tests like

1. 1. Description, pH and microbial limit test.
2. 2. Conductivity and hardness etc.