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Modification of zeo...
Modification of zeolites and synthesis of SAPO-templated carbon
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- Li, Yunxiang, 1986- (author)
- Stockholms universitet,Institutionen för material- och miljökemi (MMK)
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- Hedin, Niklas, Professor (thesis advisor)
- Stockholms universitet,Institutionen för material- och miljökemi (MMK)
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- Palmqvist, Anders, Professor (opponent)
- Materials Science, Chalmers University of Technology
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(creator_code:org_t)
- ISBN 9789176498316
- Stockholm : Department of Materials and Environmental Chemistry, Stockholm University, 2017
- English 71 s.
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Abstract
Subject headings
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- Zeolites are crystalline aluminosilicates with diverse structures and uniform porosities. They are widely used as catalysts, adsorbents and ion-exchangers in industry. Direct or post modifications optimize the performance of zeolites for different applications. In this thesis, IZM-2 and TON-type zeolites were synthesized, modified and studied. In addition, FAU-type zeolite and silicoaluminophosphate (SAPO) molecular sieves were applied as templates for the preparation of microporous carbons.In the first part of this thesis, the IZM-2 zeolite with an unknown structure was synthesized. We focused on the increasing the secondary porosity and the varied framework compositions upon post modifications.The structure determination of this IZM-2 zeolite was hindered by the small size of crystals. In the second part of this thesis, the synthesis composition was directly modified in order to increase the crystal sizes. IZM-2 crystals were enlarged by excluding the aluminium atoms from the framework. The micropores of the obtained pure-silica polymorphs were activated by ion-exchanging alkali-metal ions with protons.Typically, TON-type zeolites that are synthesized at hydrothermal conditions under stirring have needle-shaped crystals. In the third part of this thesis, snowflake-shaped aggregates were produced by using static hydrothermal conditions for the synthesis of TON-type zeolites. The effects of synthesis parameters on the growth and morphology of crystals were discussed in detail.In the last part of this thesis, microporous carbons with a structural regularity were prepared by chemical vapour deposition (CVD) of propylene using a silicoaluminophosphate (SAPO-37) template. Compared to the conventional zeolite templates, the SAPO template could be removed under mild conditions, without using hydrofluoric acid, and the generated carbons had a large specific surface area and a high fraction of ultrasmall micropores.
Subject headings
- NATURVETENSKAP -- Kemi -- Materialkemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences -- Materials Chemistry (hsv//eng)
Keyword
- microporous material
- zeolite
- SAPO templated carbon
- hydrothermal synthesis
- CVD
- post modification
- direct modification
- snowflake
- Materials Chemistry
- materialkemi
Publication and Content Type
- vet (subject category)
- dok (subject category)
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