Zeolites and their Applications
Helen M. Lang West Virginia University
Zeolite Mineralogy gy
Zeolites are framework silicates, with a completely linked framework of tetrahedra tetrahedra, each consisting of 4 O2surrounding a cation (usually Si4+ or Al3+) The framework contains open cavities in the form of channels and cages Channels and cages are occupied by H2O molecules and extra-framework extra framework cations (K+, Na+, Ca+ and others) that are commonly exchangeable Channels are large enough to allow passage of guest species In the hydrated phases, dehydration occurs at temperatures mostly below 400oC and is largely reversible (Gunter, 2001)
Lower hardness and density than other h f framework k silicates ili
Mineral Quartz Feldspars Feldspathoids Zeolites H 7 6 5-6 3.5-5.5 G . 2 65 2.65 2.54-2.75 2.15-2.5 2.0-2.4
Boiling Boiling stone stone
Many zeolites fuse readily with marked intumescence (a swelling up which results when water is expelled during heating) Zeolite comes from two Greek words meaning to boil and stone
Zeolites common properties Zeolites
High degree of hydration Low density and large void volume when hydrated y Stability of the crystal structure when dehydrated Cation exchange properties Uniform molecular-sized channels in dehydrated c ysta s crystals Ability to absorb gasses and vapors Catalytic properties
Klein, 2002
Sample Zeolite Formulas
Mineral Name Analcime Chabazite Clinoptilolite p Erionite Heulandite Laumontite M li Mesolite Scolecite Stilbite General Formula Na16[Al16Si32O96]16H2O (Ca0.5,Na,K)4[Al4Si8O24]12H2O (Na,K) ( , )6[ [Al6Si30O72] ]20H2O K2(Na,Ca0.5)8[Al10Si26O72]28H2O (Na K)Ca4[Al9Si27O72] (Na,K)Ca ]24H 24H2O Ca4[Al8Si16O48]18H2O N 16Ca Na C 16[Al48Si72O240]64H ] 64H2O Ca8[Al16Si24O80]24H2O NaCa4[Al9Si27O72]30H2O
Some characteristic Cages of Zeolites
From Armbruster & Gunter, 2001, Crystal Structures of Natural Zeolites, RIMG, v. 45
Schematic Representation of Chabazite
Chabazite Movie Jillian Banfield
Molecular Sieve Properties
Schematic illustration of how a zeolite sieve separates p a straight-chain g hydrocarbon (octane) from a branching-chain hydrocarbon (isooctane).
Structure of Heulandite-Clinoptilolite
Ten-membered and 8membered tetrahedral rings form channels parallel to the c-axis c-axis. Small green spheres represent Na, larger light blue spheres represent K, small yellow spheres represent Ca, large blue spheres represent H2O molecules.
From Armbruster & Gunter, 2001 C 2001, Crystal t l St Structures t of f Natural Zeolites, RIMG, v. 45
(Na,K,Ca0.5)7[Al7Si29O72].22H2O
Two major occurrences of Zeolites
As well-crystallized well crystallized minerals found in cavities and veins in basic igneous rocks, coarse large variety of crystal forms and coarse, habits, beautiful crystals As large deposits of fine fine-grained grained zeolites that are the diagenetic alteration products of volcanic tuffs and volcanic glass glass, recently discovered in western U.S., Cuba, Turkey Tanzania and elsewhere Turkey,
Zeolite Crystals
Heulandite - (Ca,Na)2-3Al3(Al,Si)2Si13O3612H2O from Idaho
Zeolite Crystals
Scolecite CaAl2Si3O103H 3H2O
Scolecite on Stilbite
CaAl2Si3O103H2O NaCa4[Al9Si27O72]30H2O
Mesolite Na2Ca2Al6Si9O308H2O
Zeolite Crystals
Analcime - Na16[Al16Si32O96]16H2O Isometric, trapezohedron form common
Zeolite Crystals
Stilbite (Isle of Skye) Laumontite (India)
Pretty minerals associated with zeolites
Apophyllite KCa4(Si4O10)2F-8H2O is a sheet silicate commonly assoc. with zeolites
Cavansite Ca(VO)(Si4O10)-4H2O is a sheet silicate commonly assoc. with zeolites
Properties of Zeolites
Table from Mumpton, 1999, La roca magica
CEC smectite clays 0.8 to 1.5 meq/g
Uses of Zeolites
Ammonium ion removal in waste stream treatment, sewage treatment, pet litter and aquaculture Odor control Heavy H metal t li ion removal lf from nuclear, l mine, and industrial wastes Agricultural use, such as soil conditioner and animal feed supplement
Klein, 2002
Uses of Zeolites
See La roca magica: Uses of natural zeolites in agriculture and industry FREDERICK A A. MUMPTON Proc. Natl. Acad. Sci. USA
Vol. 96, pp. 34633470, March 1999 Colloquium Paper
Construction Applications
Dimension stone altered tuff has for millennia been cut into blocks and used as g stone ( (low density, y high g p porosity, y a building homogeneity, low cost) Pozzolanic cement ( (pozzolan, pozzolanic =
a siliceous-aluminous material that will, in finely divided form and in the presence of moisture, react with CaOH to form a cement (Webster))
Popped into low density pellets for use in light-weight aggregates
Mumpton 1999
Dimension Stone
Castel Nuovo (Naples, Italy) constructed of tuffo giallo napolitano (Mumpton 1999) [the Neapolitan Yellow Tuff (12ka): eruption of Vesuvius and caldera collapse]
Waste and Wastewater Treatment
Municipal Wastewater Drinking water
Zeolite filled, water-purification tanks - Denver, CO
Mumpton 1999
Agricultural Applications
Animal nutrition and food additive Agronomy and Horticulture A Aquaculture lt Animal-waste Treatment
Mumpton 1999
Zeoponics Zeoponics
Its It s a new kind of growth medium developed by NASA for space travel Its name is from zeolite and hydroponic Its a growth medium with nutrients Its a nutrient delivery system Its an additive that makes other growth g media more effective in growing plants
Zeoponics
See http://www.zeoponix.com/ As a result of a Small Business Innovative Research contract with NASA, ZeoponiX, a small company in Louisville CO Louisville, CO, manufactures ZeoProTM, a combination of a nutrient-charged zeolite and slowly dissolving substances that contain phosphorous and other nutrients Zeoponics p is expected p to be applied pp on the International Space Station and in future missions to extra-terrestrial bodies, such as Mars and the Moon
ZeoPro is manufactured from a natural l source of f clinoptilolite li il li
Ca10(PO4)6(OH)2
Apatite Structure and Formula
OH-, F-, Cl-
Ca+2 Ca+2 Ca+2
PO43-
Ca5(PO4)3(OH,F,Cl)
Clinoptilolite Structure
Adsorption and Catalysis
Mumpton 1999
Nuclear Waste and Fallout
Mumpton 1999
Other Applications
Consumer Products Medical Applications
Mumpton 1999
Structure of Heulandite-Clinoptilolite
Ten-membered and 8membered tetrahedral rings form channels parallel to the c-axis c-axis. Small green spheres represent Na, larger light blue spheres represent K, small yellow spheres represent Ca, large blue spheres represent H2O molecules.
(Na,K,Ca0.5)7[Al7Si29O72].22H2O
Sample Zeolite Formulas
Mineral Name Analcime Chabazite Clinoptilolite Erionite Heulandite Laumontite Mesolite Scolecite Stilbite General Formula Na16[Al16Si32O96]16H2O (Ca0.5,Na,K)4[Al4Si8O24]12H2O (Na,K)6[Al6Si30O72]20H2O K2(Na,Ca0.5)8[Al10Si26O72]28H2O (Na K)Ca4[Al9Si27O72]24H2O (Na,K)Ca Ca4[Al8Si16O48]18H2O Na16Ca16[Al48Si72O240]64H2O [Al16Si24O80] ]24H2O Ca8[ NaCa4[Al9Si27O72]30H2O
