Ion exchange on zeolites

Sodium ion exchange. Sodium ion exchange on zeolites (Section 7.3) or on synthetic organic cation-exchange resins such as Dowex-50 (a sulfonated polystyrene Fig. 14.1), in most circumstances, is superior to the above softening methods.13 The exchange process favors binding of Ca2+ or Mg2+ over Na+ in the solid resin phase ... 

Zeolites have very specific ion exchange sites and ion exchange is the most common method used to introduce metal ions into zeolite cages. Ion exchange on zeolites can be highly adsorption controlled and pure metal ions can be used as precursors. 

---