What are Ion Exchange resins?

CrossAfrica Water solutions utilises ion exchange as an additional step in the water filtration process.

Ion exchange (IE) is a water treatment method where one or more undesirable contaminants are removed from water by exchange with another non-objectionable, or less-objectionable substance. Both the contaminant and the exchanged substance are dissolved and have the same type (+,-) of electrical charge.

IE is another version of water softening, and is employed in a modular capacity with CrossAfrica Water’s existing commercial or point-of-entry micro-filtration solutions.

Ion exchange is a reversible chemical reaction where dissolved ions are removed from a solution, and replaced with other ions of the same or similar electrical charge. Not a chemical reactant in and of itself, IX resin is instead a physical medium that facilitates ion exchange reactions. The resin itself is composed of organic polymers that form a network of hydrocarbons. Throughout the polymer matrix are ion exchange sites, where so-called “functional groups” of either positively-charged ions (cations) or negatively-charged ions (anions) are affixed to the polymer network. These functional groups readily attract ions of an opposing charge

How does ion exchange resin work?

To fully understand how IX resins work, it is important to first understand the principles of the ion exchange reaction. Put simply, ion exchange is a reversible interchange of charged particles – or ions – with those of similar charge. This occurs when ions present on an insoluble IX resin matrix effectively swap places with ions of a similar charge that are present in a surrounding solution.

The IX resin functions this way because of its functional groups, which are essentially fixed ions that are permanently bound within the polymer matrix of the resin. These charged ions will readily bond with ions of an opposing charge, which are delivered through the application of a counterion solution. These counterions will continue to bond with the functional groups until equilibrium is reached.