Zeolites are hydrated aluminosilicate minerals made from interlinked tetrahedra of alumina (AlO4) and silica (SiO4).
In simpler words, they're solids with a relatively open, three-dimensional crystal structure built from the elements aluminum, oxygen, and silicon, with alkali or alkaline-Earth metals (such as sodium, potassium, and magnesium) plus water molecules trapped in the gaps between them.
Zeolites form with many different crystalline structures, which have large open pores (sometimes referred to as cavities) in a very regular arrangement and roughly the same size as small molecules.
What special properties do Zeolites have?
Zeolites are very stable solids that resist the kinds of environmental conditions that challenge many other materials.
High temperatures don't bother them because they have relatively high melting points (over 1000°C), and they don't burn.
They also resist high pressures, don't disssolve in water or other inorganic solvents, and don't oxidize in the air.
What are Zeolites used for?
The cage-like structure of zeolites makes them useful in all sorts of ways. One of the biggest everyday uses for zeolites is in water softeners and water filters.
In ion-exchange water softeners, for example, hard water (rich in calcium and magnesium ions) is piped through a column filled with sodium-containing zeolites.
The zeolites trap the calcium and magnesium ions and release sodium ions in their place, so the water becomes softer but richer in sodium.
Many everyday laundry and dishwasher detergents contain zeolites to remove calcium and magnesium and soften water so they work more effectively.
Two other very common, everyday uses of zeolites are in odor control and pet litter; in both, the porous crystalline structure of the zeolites helps by trapping unwanted liquids and odor molecules.
This simple idea, so effective in our homes, has much more important uses outside them: zeolites have proved extremely effective at removing radioactive particles from nuclear waste and cleaning up soils contaminated with toxic heavy metals.
The many other uses for zeolites including concrete production, soil-conditioners, and animal food.
