Description; Introduction To Softeners; Softening Principles - Pentair Riversoft Installer Manual

Installer Manual Riversoft - Description
3.

Description

3.1.

Introduction to softeners

3.1.1. Softening principles

Softening is an ion exchange process where the hard ions are getting exchange by soft ions, typically
sodium or potassium. This is achieved by placing the water in contact with an ion exchange resin and
ensuring the contact time is appropriate for the flow rate to produce.
The basic chemistry of softening resins is very simple: the resin is made of small polymer beads with
chemical functionality that selectively captures the divalent ions (such as Ca
ions) and releases in exchange less tightly held monovalent ions, usually sodium (Na
frequently potassium. Here below is shown the chemical reactions mechanism for softening:
Hardness
The means that under certain conditions, the reactions can be reversed. This is due to the
equilibrium between the water composition and the amount of hardness that can be removed. This
reverse reaction is observed at different kinetics and at high monovalent ions concentration. Usually
for softening this conditions are obtained using concentrated NaCl (or KCl) solutions that are put in
contact with the resin. This is called regeneration:
Saturated Exhausted
brine resin bead
12 / 90
Resin bead
2+
and Mg
Exhausted resin
bead
Regenerated Waste
resin bead
Ref. MKT-IM-045 / A - 13.03.2020
2+
- hardness
+
) or less
Soft water
Excess
salt