Zeoliittimineraalit

Zeoliittimineraalit is a family of hydrated aluminosilicate minerals. Their characteristic structure consists of a three-dimensional framework of silica and alumina tetrahedra, with alkali and alkaline earth cations and water molecules occupying interstitial spaces within this framework. This unique cage-like structure gives zeolites their most important property: cation exchange capacity and molecular sieving ability.

The framework of zeolites is formed by the linkage of SiO4 and AlO4 tetrahedra, creating channels and cavities of varying sizes. The presence of aluminum in the framework introduces a negative charge, which is balanced by exchangeable cations such as sodium, potassium, calcium, and magnesium. These cations can be readily exchanged with other cations present in the surrounding solution, a process fundamental to many zeolite applications.

Zeolites occur naturally in volcanic rocks and sediments, often formed by the interaction of volcanic glass with groundwater. They are also synthesized industrially for a wide range of applications. Their porous structure allows them to selectively adsorb molecules based on size and shape, acting as molecular sieves. This property, along with their ion-exchange capabilities, makes them valuable in catalysis, water purification, gas separation, and as detergents. Common natural zeolites include clinoptilolite, heulandite, and chabazite.