Dealumination of large crystals of zeolite ZMS-5 by various methods

Kornatowski, J.; Baur, W. H.; Pieper, G.; Rozwadowski, M.; Schmitz, W.; Cichowlas, Andrzej A.

doi:10.1039/ft9928801339

Cited by 37 publications

(14 citation statements)

References 9 publications

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“…Silica gel was transformed into microcrystalline balls of silicalite (34) and into various ordered shapes (35). ZSM-5 crystals were de-aluminated by acid leaching/steaming/acid leaching and other methods (36)(37)(38)(39)(40)(41). From the complex literature on adsorption of organic molecules into the ZSM-5-silicalite and catalytic activity, the following representative papers are selected: linear decrease of hydrophobicity with Al substitution (42); methanol adsorption on acidic ZSM-5 and conversion to gasoline, xylene, etc.…”

mentioning

confidence: 99%

Biochemical evolution. I. Polymerization on internal, organophilic silica surfaces of dealuminated zeolites and feldspars

Smith

1998

Proc. Natl. Acad. Sci. U.S.A.

117

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Catalysis at mineral surfaces might generate replicating biopolymers from simple chemicals supplied by meteorites, volcanic gases, and photochemical gas reactions. Many ideas are implausible in detail because the proposed mineral surfaces strongly prefer water and other ionic species to organic ones. The molecular sieve silicalite (Union Carbide; ‫؍‬ Al-free Mobil ZSM-5 zeolite) has a three-dimensional, 10-ring channel system whose electrically neutral Si-O surface strongly adsorbs organic species over water. Three -O-Si tetrahedral bonds lie in the surface, and the fourth Si-O points inwards. In contrast, the outward Si-OH of simple quartz and feldspar crystals generates their ionic organophobicity. The ZSM-5-type zeolite mutinaite occurs in Antarctica with boggsite and tschernichite (Al-analog of Mobil Beta). Archean mutinaite might have become de-aluminated toward silicalite during hot/cold/wet/dry cycles. Catalytic activity of silicalite increases linearly with Al-OH substitution for Si, and Al atoms tend to avoid each other. Adjacent organophilic and catalytic Al-OH regions in nanometer channels might have scavenged organic species for catalytic assembly into specific polymers protected from prompt photochemical destruction. Polymer migration along weathered silicic surfaces of micrometer-wide channels of feldspars might have led to assembly of replicating catalytic biomolecules and perhaps primitive cellular organisms. Silica-rich volcanic glasses should have been abundant on the early Earth, ready for crystallization into zeolites and feldspars, as in present continental basins. Abundant chert from weakly metamorphosed Archaean rocks might retain microscopic clues to the proposed mineral adsorbent/catalysts. Other framework silicas are possible, including ones with laevo/dextro one-dimensional channels. Organic molecules, transition-metal ions, and P occur inside modern feldspars.

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mentioning

confidence: 99%

Biochemical evolution. I. Polymerization on internal, organophilic silica surfaces of dealuminated zeolites and feldspars

Smith

1998

Proc. Natl. Acad. Sci. U.S.A.

117

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“…Das H 2 O-Adsorptionsvermögen von Y-Zeolithen in der Natrium-Form wurde von O T T E N [9] und W E I T K A M P [10] [11].…”

Section: Zielsetzungunclassified

Einsatz modifizierter ZSM‐5‐Zeolithe zur Entfernung von Ammoniak aus wassergesättigten Gasströmen

Streich¹,

Rauscher²

2003

Chemie Ingenieur Technik

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“…Irreversible thermal deactivation occurs at >650 °C with deactivation temperatures decreasing in the presence of water vapors which are normally present in the automotive exhaust . The structural collapse of zeolites and the outmigration of active components is attributed to the deactivation at 650 °C while dealumination is believed to deactivate zeolites at 500 °C . Reactive olefins form carbonaceous deposits while participating in the reduction of NO x .…”

Section: Automotive Catalystsmentioning

confidence: 99%

Materials Chemistry Issues Related to Advanced Materials Applications in the Automotive Industry

et al. 1996

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The driving force behind the research on advanced materials has largely been aerospace and defense applications. In such applications the customer-induced limitations and infrastructural economic factors are secondary to the application-oriented parameters. Automobiles, on the other hand, represent the primary consumers of advanced materials in civilian applications. Automobiles are high-technology, low-cost machines which need to be robust for various climatic conditions and driver behavior. Advanced materials play an important role in the design and fabrication of various components of automobiles, and the use of new materials continues to increase. Recent interest in developing highly fuel efficient vehicles with low emissions has focused efforts toward materials, designs, and devices and is spurring research into advanced materials for weight reduction. The goal is to achieve fuel efficiency by weight reduction and a more efficient powertrain. In this review article, we summarize the efforts of the 1970s and the 1980s on the development of ceramic gas turbine engines with emphasis on materials processing and properties. This is followed by a discussion of metal-matrix composites and reinforced plastics, the structural materials of current interest. The materials issues related to automotive exhaust reduction catalysts are discussed since materials continue to play an important role in designing catalysts to meet the new EPA regulations. The understanding of materials chemistry is expected to play an important role in designing new materials and developing new processes that can be used economically to mass produce vehicle components. We also summarize reports based on ceramic precursor technology and sol-gel processes that show promise in the fabrication of automotive components.

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Dealumination of large crystals of zeolite ZMS-5 by various methods

Cited by 37 publications

References 9 publications

Biochemical evolution. I. Polymerization on internal, organophilic silica surfaces of dealuminated zeolites and feldspars

Biochemical evolution. I. Polymerization on internal, organophilic silica surfaces of dealuminated zeolites and feldspars

Einsatz modifizierter ZSM‐5‐Zeolithe zur Entfernung von Ammoniak aus wassergesättigten Gasströmen

Materials Chemistry Issues Related to Advanced Materials Applications in the Automotive Industry

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