Ion Exchange

Ion exchange and exchange resins have numerous applications. In scientific studies, exchange resins are used to isolate and collect various ionic species, cations on a cation resin, and anions on an anion resin. In industry resins are used to purify water by removing all ions from it. Upon passage of a water sample through both a cation resin (H⁺ form) and an anion resin (OH^- form) the cations and anions in the water are retained. The H⁺ and OH^- ions released from the resin then combine to form additional water. Deionized water also is a source of pure water containing no ionic chemical compounds.

Ion exchange also is used to remove ionic compounds from boiler water used in the steam generation of electric power. Ion exchange resins also are used in the separation and purification of various chemicals. Rare earth elements are separated from their ores and purified in this manner.