Water softening is the reduction of the concentration of calcium, magnesium, and certain other metal cations in hard water. These "hardness ions" can cause a variety of undesired effects including galvanic corrosion, interfering with the action of soaps, and the build up of limescale, which can foul plumbing.Conventional water-softening appliances intended for household use depend on an ion-exchange resin in which hardness ions are exchanged for sodium ions. Water softening may be desirable where the source of water is hard.
Water softening methods mainly rely on the removal of Ca2+ and Mg2+ from a solution or the sequestration of these ions, i.e. binding them to a molecule that removes their ability to form scale or interfere with soaps. Removal is achieved by exchange of ions and by precipitation methods. Sequestration entails the addition of chemical compounds called sequestration (or chelating) agents.
There has been significant technological development in automation and as a result of these now a days water softners are automatic in the sense that one does not have to regenerate or recharge resins with NaCl manually. This job is done by timer devices and sequential automatically operated valves.
Akar manufactures and supplies Softeners for industrial applications. Sown in the picture above is a Super Softener supplied to a research establishment in India.
Ion-exchange materials contain sodium ions (Na+) that are electrostatically bound and that are readily replaced by hardness ions such as Ca2+ and Mg2+. Ion exchange resins are organic polymers containing anionic functional groups to which the Na+ is bound. Minerals called zeolites also exhibit ion-exchange properties; these minerals are widely used in laundry detergents.