Softening by ion exchange
resin is also known as Base Exchange softening. It is the most
common and probably the easiest method of removing hardness like
calcium & magnesium from water and renders the water suitable
for utility purpose. As the name implies ion exchange is a
process in which undesirable ions are exchanged for more
desirable ions.
Process
It consist of passing raw water
containing hardness through a bed of cat ion resin in sodium
form. The hardness ions Ca & Mg are taken up by resin and in
exchange sodium ions are relinquished from the resin. Raw water
will continue to get softened till the resin gets exhausted.
Bringing back the resin to its original form is called
regeneration. Softener resin is regenerated by sodium chloride
of 10 – 15
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