Sunday, May 21, 2006

Problems with hard water

Waters that have been in contact with limestone and other sediments tend to acquire dissolved ions, mainly of calcium Ca2+ and magnesium Mg2+. The positive electrical charges of these ions are balanced by the presence of anions (negative ions), of which bicarbonate HCO3– and carbonate CO32– are the most important. These ions have their origins in carbon dioxide which is present in all waters exposed to the atmosphere and also in groundwaters. Water softeners heldissipatete this.

These "hardness ions" cause two major kinds of problems:

* The metal ions react with soaps and calcium sensitive detergents), hindering their ability to lather properly and forming an unsightly precipitate— the familiar scum or "bathtub ring". Presence of "hardness ions" also inhibits the cleaning effect of detergent formulations.
* More seriously, calcium and magnesium carbonates tend to precipitate out as adherent solids on the surfaces of pipes and especially on the hot heat exchanger surfaces of boilers. The resulting scale buildup can restrict water flow in pipes. In boilers, the deposits act as thermal insulation that impedes the flow of heat into the water; this not only reduces heating efficiency, but allows the metal to overheat which, in a pressurized system, can lead to catastrophic failure.

Conventional water-softening devices intended for household use depend on an ion-exchange resin in which "hardness" ions trade places with sodium that are electrostatically bound to the anionic functional groups of the polymeric resin . A class of minerals known as zeolites also exhibit ion-exchange properties and were widely used in earlier water softeners.

Water Softener - Resource


Anonymous Anonymous said...

Hard water is something that most of us get in our homes. What makes the water 'hard' is the high amount of minerals in it. If you don't have a water softener, then you might be getting some nasty soap scum deposits on your tub or shower walls. I would suggest that if you don't have a water softener, that you might want to look into it.

3:09 PM  

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