Ion exchange allows the selective removal of dissolved ions from the aqueous phase. In practice, ion exchange is used in particular for binding heavy metal ions.
Positively or negatively charged resins are used as ion exchangers, through which dissolved ions from the water to be treated are exchanged with ions of the same charge. In water treatment, ion exchangers are primarily used as columns filled with an ion exchanger material.
If the exchange capacity of the resins is exhausted, they can be regenerated by acids, bases or electroentionization and then reused.
In practice, the selective ion exchange resins are suitable, inter alia, for the removal of dissolved heavy metal ions from the raw water. Therefore, in practice, ion exchange is often used in combination with other upstream processes (e.g. precipitation, flocculation) for Heavy metal removal used.