ion‐exchange resin An organic compound that will adsorb ions under some conditions and release them under others. The best‐known example is in water‐softening, where calcium ions are removed from the water by binding to the resin, displacing sodium ions. The resin is then regenerated by washing with a concentrated solution of salt, when the sodium ions displace the calcium ions. Ion‐exchange resins are used for purification of chemicals, metal recovery, and a variety of analytical techniques.

resins, ion‐exchange See ion‐exchange resins.