jaanioninvaihtohartseja

Jaanioninvaihtohartseja are polymeric resins used to remove negatively charged ions (anions) from liquids by exchanging them with counterions fixed to the resin. They are typically based on cross‑linked styrene‑divinylbenzene matrices that carry positively charged functional groups, most commonly quaternary ammonium groups. In operation, the resin is loaded in a specific form, such as chloride or hydroxide, and when contacted with a solution containing target anions, those ions are exchanged with the resin’s bound counterions. The ion-exchange capacity is usually expressed in milliequivalents per gram (meq/g) and depends on the density of functional groups and the degree of cross‑linking.

Two main classes exist: strong-base anion exchangers, which have permanently charged quaternary ammonium groups and function over a wide pH range; and weak-base exchangers, which rely on amine groups that are active mainly at higher pH when deprotonated. The physical structure, including porosity and cross‑link density, influences mass-transfer characteristics and selectivity; macroporous resins can improve performance for larger or more hindered anions.

Applications are widespread in water treatment and chemical processing. They are used to remove various inorganic anions such as nitrate, sulfate, chloride, and certain organic anions, and to support mixed‑bed deionization when paired with cation exchangers for complete demineralization. Regeneration typically involves flushing with a concentrated solution (for example NaOH or NaCl) to restore the resin to its original form. Limitations include competitive ion effects, fouling by organics, and resin aging, which can reduce capacity over time. See also ion-exchange resin, cation exchange resin, water purification.