Anioninvaihtoreikiä

Anioninvaihtoreikiä, known in English as anion exchange resins, are a type of ion-exchange material that contains positively charged functional groups. These functional groups attract and bind negatively charged ions, or anions, from a solution. The resins are typically insoluble polymer beads, often made from styrene-divinylbenzene copolymers, with quaternary ammonium groups attached to the polymer matrix. These quaternary ammonium groups carry a fixed positive charge and a mobile counter-ion, usually chloride or hydroxide.

The primary function of anion exchange resins is to remove unwanted anions from water or other solutions, or to concentrate specific anions. This process, called anion exchange, involves the exchange of the mobile counter-ion on the resin with an anion of similar charge from the surrounding solution. For example, in water purification, anion exchange resins can remove anions like sulfate, nitrate, and silicate.

Anion exchange resins are widely used in various applications, including water softening and demineralization, where they work in conjunction with cation exchange resins to remove all dissolved ionic impurities. They are also employed in industrial processes such as chemical purification, the removal of color and organic impurities from sugar solutions, and in analytical chemistry for sample preparation and separation. The capacity and selectivity of an anion exchange resin depend on the type of functional group, the cross-linking of the polymer, and the operating conditions. They can be regenerated by washing with a concentrated solution of a salt containing the original mobile counter-ion.