Zeolites and their ApplicationsZeolites and their Applications

Helen M. LangWest Virginia University

Zeolite Mineralogygy• Zeolites are framework silicates, with a completely linked

framework of tetrahedra each consisting of 4 O2-framework of tetrahedra, each consisting of 4 Osurrounding 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 cations (K+ Na+ Ca+ and others) that areextra 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)

temperatures mostly below 400 C and is largely reversible

Lower hardness and density than h f k iliother framework silicates

• Mineral H G .• Quartz 7 2 65• Quartz 7 2.65• Feldspars 6 2.54-2.75• Feldspathoids 5-6 2.15-2.5• Zeolites 3.5-5.5 2.0-2.4

“Boiling stone”Boiling stone

• Many zeolites fuse readily with markedMany zeolites fuse readily with marked intumescence (a swelling up which results when water is expelled during heating)when water is expelled during heating)

• Zeolite comes from two Greek words meaning to boil and stonemeaning to boil and stone

Zeolites’ common propertiesZeolites common properties

• High degree of hydrationHigh degree of hydration• Low density and large void volume when

hydratedy• Stability of the crystal structure when dehydrated• Cation exchange propertiesCation exchange properties• Uniform molecular-sized channels in dehydrated

crystalsc ysta s• Ability to absorb gasses and vapors• Catalytic propertiesCatalytic properties

Klein, 2002

Sample Zeolite FormulasMineral Name General Formula

Analcime Na16[Al16Si32O96]·16H2O

Chabazite (Ca0.5,Na,K)4[Al4Si8O24]·12H2O

Clinoptilolite (Na,K)6[Al6Si30O72]·20H2Op ( , )6[ 6 30 72] 2

Erionite K2(Na,Ca0.5)8[Al10Si26O72]·28H2O

Heulandite (Na K)Ca [Al Si O ]·24H OHeulandite (Na,K)Ca4[Al9Si27O72] 24H2O

Laumontite Ca4[Al8Si16O48]·18H2O

M li N C [Al Si O ] 64H OMesolite Na16Ca16[Al48Si72O240]·64H2O

Scolecite Ca8[Al16Si24O80]·24H2O

Stilbite NaCa4[Al9Si27O72]·30H2O

Some characteristic Cages of ZeolitesSome 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 PropertiesMolecular Sieve Properties

Schematic illustration of how a zeolite sieve separates a straight-chain p ghydrocarbon (octane) from a branching-chain hydrocarbon (isooctane).

Structure of Heulandite-Clinoptilolite

Ten-membered and 8-membered tetrahedral rings form channels parallel to the c-axisparallel to the c-axis. Small green spheres represent Na, larger light blue spheres represent K, small yellow spheres represent Ca, large blue spheres represent H2O molecules.molecules.

From Armbruster & Gunter, 2001 C t l St t f

(Na,K,Ca0.5)7[Al7Si29O72].22H2O

2001, Crystal Structures of Natural Zeolites, RIMG, v. 45

Two major occurrences of ZeolitesTwo major occurrences of Zeolites

• As well-crystallized minerals found inAs well crystallized minerals found in cavities and veins in basic igneous rocks, coarse large variety of crystal forms andcoarse, large variety of crystal forms and habits, beautiful crystals

• As large deposits of fine grained zeolites• As large deposits of fine-grained zeolites that are the diagenetic alteration products of volcanic tuffs and volcanic glassof volcanic tuffs and volcanic glass, recently discovered in western U.S., Cuba, Turkey Tanzania and elsewhereTurkey, Tanzania and elsewhere

Zeolite Crystals

Heulandite - (Ca,Na)2-3Al3(Al,Si)2Si13O36·12H2Ofrom Idaho

Zeolite Crystals

Scolecite –CaAl Si O ·3H OCaAl2Si3O10 3H2O

Scolecite on StilbiteCaAl2Si3O10·3H2O – NaCa4[Al9Si27O72]·30H2O

Mesolite – Na2Ca2Al6Si9O30·8H2O

Zeolite CrystalsZeolite Crystals

Analcime - Na16[Al16Si32O96]·16H2OIsometric, trapezohedron form common

Zeolite CrystalsZeolite Crystals

Laumontite (India)

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 ZeolitesProperties of Zeolites

CEC smectite clays0.8 to 1.5 meq/g

Table from Mumpton, 1999, La roca magica

Uses of ZeolitesUses of Zeolites

• Ammonium ion removal in waste streamAmmonium ion removal in waste stream treatment, sewage treatment, pet litter and aquacultureaquaculture

• Odor controlH t l i l f l• Heavy metal ion removal from nuclear, mine, and industrial wastes

• Agricultural use, such as soil conditioner and animal feed supplement

Klein, 2002

Uses of ZeolitesUses of Zeolites

• See La roca magica: Uses of naturalSee La roca magica: Uses of natural zeolites in agriculture and industry

• FREDERICK A MUMPTON• FREDERICK A. MUMPTON• Proc. Natl. Acad. Sci. USA

Vol. 96, pp. 3463–3470, March 1999Colloquium Paper

Construction ApplicationsConstruction Applications

• Dimension stone – altered tuff has forDimension stone altered tuff has for millennia been cut into blocks and used as a building stone (low density, high porosity, g ( y g p yhomogeneity, 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))react with CaOH to form a cement (Webster))

• Popped into low density pellets for use in light-weight aggregateslight-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• Drinking water

Mumpton 1999Zeolite –filled, water-purification tanks - Denver, CO

Agricultural ApplicationsAgricultural Applications

• Animal nutrition and food additiveAnimal nutrition and food additive• Agronomy and Horticulture

A lt• Aquaculture• Animal-waste Treatment

Mumpton 1999

“Zeoponics”Zeoponics

• It’s a new kind of growth mediumIt s a new kind of growth medium developed by NASA for space travel

• Its name is from zeolite and hydroponic• Its name is from zeolite and hydroponic• It’s a growth medium with nutrients• It’s a nutrient delivery system• It’s 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 manufactures ZeoProTMLouisville, CO, manufactures ZeoPro , a combination of a nutrient-charged zeolite and slowly dissolving substances that contain phosphorous and otherthat contain phosphorous and other nutrients

• Zeoponics is expected to be applied on p p ppthe International Space Station and in future missions to extra-terrestrial bodies, such as Mars and the Moonbodies, such as Mars and the Moon

ZeoPro is manufactured from a l f li il linatural source of clinoptilolite

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 CatalysisAdsorption and Catalysis

Mumpton 1999

Nuclear Waste and FalloutNuclear Waste and Fallout

Mumpton 1999

Other ApplicationsOther Applications

• Consumer ProductsConsumer Products• Medical Applications

Mumpton 1999

Structure of Heulandite-Clinoptilolite

Ten-membered and 8-membered tetrahedral rings form channels parallel to the c-axisparallel to the c-axis. Small green spheres represent Na, larger light blue spheres represent K, small yellow spheres represent Ca, large blue spheres represent H2O molecules.molecules.

(Na,K,Ca0.5)7[Al7Si29O72].22H2O

Sample Zeolite Formulas

Mineral Name General FormulaMineral Name General Formula

Analcime Na16[Al16Si32O96]·16H2O

Chabazite (Ca0.5,Na,K)4[Al4Si8O24]·12H2O

Clinoptilolite (Na,K)6[Al6Si30O72]·20H2O

Erionite K2(Na,Ca0.5)8[Al10Si26O72]·28H2O

Heulandite (Na K)Ca [Al Si O ]·24H OHeulandite (Na,K)Ca4[Al9Si27O72]·24H2O

Laumontite Ca4[Al8Si16O48]·18H2O

Mesolite Na16Ca16[Al48Si72O240]·64H2O

Scolecite Ca8[Al16Si24O80]·24H2O 8[ 16 24 80] 2

Stilbite NaCa4[Al9Si27O72]·30H2O