THE
PRICIPLE OF ION EXCHANGE
The
most common water softening method called "ion exchange,"
is a reversible chemical process of exchanging hard water ions
for soft water ions. Calcium and magnesium are the hardness ions,
sodium can be considered the "softness" ions and they
are exchanged to create soft water.
Ion
exchange takes place in a "resin bed" made up of tiny
bead-like material often made of styrene and divynlbenzene. The
beads, having a negative charge, attract and hold positively charged
ions such as sodium, but will exchange them whenever the beads
encounter another positively charged ion, such as calcium or magnesium
minerals. This ion exchange happens very easily since the sodium
ions have a positive charge of only one, while magnesium and calcium
have a more powerful positive charge of two. A further explanation
is available in the Cycle Information Chart.
