Ion exchange is a highly versatile water treatment technology that tackles many different problems.

Issue: 3/05

Most readers will have enough understanding of the word "ion"

Why Ion Exchange?

Many ions can have negative effects either on the mechanical parts of a process or in our bodies. For example, most people are aware of hardness deposits caused by calcium and magnesium, or "blue baby"

The Importance of Resin

After all the discussion about ions in water and how they get there, the true discussion about ion exchange starts with resin. Resins are tiny plastic beads that act as the backbone, or structure, on which ion exchange can happen. Resins are made from different plastics and can be a variety of different colors. They can also have a variety of different functions, which will be discussed in a moment.

On a sub-microscopic level, it is useful to think of resin as a tiny ball of long strings all bunched together. Let's assume that in order to keep the ball from unraveling, some of the loops of string are tied together by shorter pieces of string, or "ties,"


Now that the fundamental operation of ion exchange resin is understood, specific applications can be discussed. By far, the most widely known application of ion exchange is softening. As the name implies, softening is simply removal of the scale-forming hardness ions (calcium and magnesium) from water.

Based on their names, it is easy to tell that the calcium and magnesium ions are positively charged cations. Thus, a cation resin is used.

After being in hardness-removal service for a period of time, the resin bed becomes loaded with water hardness cations, and it is time to "regenerate"