Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents and catalysts.
Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents and catalysts.The term zeolite was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that rapidly heating a material, believed to have been stilbite, produced large amounts of steam from water that had been adsorbed by the material. Based on this, he called the material zeolite, from the Greek ζέω (zéō), meaning “to boil” and λίθος (líthos), meaning “stone”.The classic reference for the field has been Breck’s book Zeolite Molecular Sieves: Structure, Chemistry, And Use.
Zeolites occur naturally but are also produced industrially on a large scale. As of December 2018, 253 unique zeolite frameworks have been identified, and over 40 naturally occurring zeolite frameworks are known.Every new zeolite structure that is obtained is examined by the International Zeolite Association Structure Commission and receives a three letter designation.
Zeolites have a porous structure that can accommodate a wide variety of cations, such as Na+, K+, Ca2+, Mg2+ and others. These positive ions are rather loosely held and can readily be exchanged for others in a contact solution. Some of the more common mineral zeolites are analcime, chabazite, clinoptilolite, heulandite, natrolite, phillipsite, and stilbite. An example of the mineral formula of a zeolite is: Na2Al2Si3O10·2H2O, the formula for natrolite. Cation exchanged zeolites possess different acidity and catalyse different reactions.