ABSTRACT
Molecular sieve zeolites are crystalline, hydrated aluminosilicates of Na, K, Mg, Ca, Sr, and Ba cations. The aluminosilicate portion of the structure is a three-dimensional open framework consisting of a network of AlO4 and SiO4 tetrahedra linked to each other by sharing all of the oxygens. Molecular sieve zeolite ion exchangers provide many unique combinations of cation exchange selectivity, capacity, and stability not available in other inorganic or organic ion exchangers. The discovery by R. M. Milton and co-workers at Union Carbide that zeolites could be synthesized at convenient conditions from reactive raw materials led to the discovery of dozens of new zeolite structures. The growing knowledge of zeolite ion exchangers' properties, together with growing needs for selective, stable ion exchangers in pollution abatement, water treatment, energy production, agriculture, aquaculture, animal nutrition, metals processing, and biomedical applications promise an exciting future in new applications of these unique materials.
