# Cross-linked polystyrene and ion exchanger

## Regeneration of ion exchangers

Ion exchangers can be regenerated. Exhausted exchangers, in which all ions have been exchanged, can thus be restored to their original shape. For example, cation exchangers can be incorporated into the ${\text{H}}^{+}$-Be molded. This is possible because the exchange reaction is reversible.

$N / A++R.−H+⇌H++R.−N / A+$

By increasing the ${\text{H}}^{+}$-Concentration, the equilibrium can be shifted to the left. Correspondingly, strongly basic anion exchangers can be reintroduced into the $\text{O}{\text{H}}^{-}$-Be brought into shape. The free amino groups of weakly basic anion exchangers can already be restored with ammonia or sodium carbonate solution.