Zeolite

File:ZeolitesUSGOV.jpg

Natural zeolite with a U.S. penny for scale

Zeolites are a type of mineral made of mostly alumina and silica (an aluminosilicate). They are microporous, meaning they contain tiny holes called pores. Zeolite is commonly used in commercial absorbants and catalysts. In addition to natural zeolite rocks, many synthetic zeolites have been made by people.

The name zeolite was given in 1756 by Swedish mineralogist Axel Fredrik Cronstedt. He called the material zeolite, from the Greek ζέω (zéō), meaning "to boil" and λίθος (líthos), meaning "stone".

Occurrence

Natural zeolites form where volcanic rocks and ash react with alkaline groundwater. Zeolites found in nature are almost never pure. They are contaminated by other minerals, metals, quartz, or other zeolites.

Uses

Zeolites can be used in domestic and commercial water purification, water softening, and other uses. Zeolites were also found to help silver naturally emit light, which may compete with fluorescent lights or LEDs.

Zeolites can be used to store solar heat harvested from solar thermal collectors. The largest use for zeolite is the global laundry detergent market.

Synthetic zeolites are widely used in the chemical industry. The crystal structure of synthetic zeolite can be carefully designed to control the size of the pores, allowing it to serve as a molecular sieve that separates molecules by shape and size. The structure can also be designed to control how it acts as a catalyst, or as a scaffold for other crystals to be grown on.

Zeolite Media

• FAU and LTA.png

  Frameworks of LTA-type (left) and FAU-type zeolites (right)

• Zeolite structure as an assembly of tetrahedra.png

  Microscopic structure of a zeolite (mordenite) framework, assembled from corner-sharing SiO₄ tetrahedra. Sodium is present as an extra-framework cation (in green). Si atoms can be partially replaced by Al or other tetravalent metals.

• Zeolite Mordenite (with Al substitution).png

  Zeolite Mordenite with some Si atoms substituted with Al atoms

• Zeolite4ring.svg

  Three ways to represent the oxygen 4-membered ring structure of silicate compounds

• Estonian Museum of Natural History Specimen No 203540 photo (g232 g232-25 jpg).jpg

  Zeolite exhibited in the Estonian Museum of Natural History

• Natrolit, Gracza 2Polska.jpg

  natrolit, pochodzenie Polska, Gracza; autor zdjęcia Dagmara Lesiów; 20.o8.2006r

• Ceolite nax.JPG

  Extruded granules - NaX synthetic zeolite

• U.S. Department of Energy - Science - 463 015 001 (10190451506).jpg

  A researcher at Sandia National Laboratories examines vials of SOMS (Sandia Octahedral Molecular Sieve), a zeolite that shows potential for radioactive waste and industrial metals cleanup.

• Pressure swing adsorption principle.svg

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• Stilbite-Ca-Natrolite-Laumontite-247898.jpg

  A combination specimen of four zeolite species. The radiating natrolite crystals are protected in a pocket with associated stilbite. The matrix around and above the pocket is lined with small, pink-colored laumontite crystals. Heulandite is also present as a crystal cluster on the backside.