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In-situ studies of thin film zeolite catalysts using FTIR/ATR spectroscopy
2009 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Zeolite films have a great potential as structured catalysts, membranes and sensors in various novel technological applications. Combining zeolite membrane films with chemical reactors results in a membrane reactor which may offers better product selectivity and conversion as compared to conventional reactors. In addition, miniaturization of reactors along with the introduction of structured catalysts promises more efficient, cleaner, safer and selective operations. But till date, due to lack of sufficient knowledge in this domain, research in the field of membrane reactors as well as in microreactor technology remain relative scarce. A powerful characterization technique is needed for investigating the performance of zeolite film catalysts, one such promising technique is FTIR/ATR spectroscopy (Fourier transform infrared/ attenuated total reflection spectroscopy). In this work, zeolite ZSM-5 films were synthesized on ZnS ATR elements by an in-situ method. The films were subsequently activated by introducing Brönstedt acid sites. Xylene isomerisation reaction was successfully studied at in the temperature range 393-473K. At a constant partial pressure of p-xylene in the feed (828 Pa), the adsorption of xylene isomers was, as expected, found to be higher at lower temperatures. Furthermore the meta-/ortho-xylene ratio was observed to decrease with increasing reaction temperature. Further,during the desorption process, p- xylene and o-xylene desorbs in the order p-xylene > o-xylene, whereas m- xylene due to high diffusion limitation in the ZSM-5 film, remains constant throughout the desorption process. Besides the xylene isomers bands in IR spectra, coke was also observed and whose concentration is found to be increasing with reaction temperature and moreover it remains in the film during the desorption process. The observations indicate that the FTIR/ATR technique could be used as a characterization technique for investigating the performance as well as reaction & its kinetics occurring on active film at different temperatures and pressures.

Place, publisher, year, edition, pages
Keyword [en]
Physics Chemistry Maths
Keyword [sv]
Fysik, Kemi, Matematik
URN: urn:nbn:se:ltu:diva-50093ISRN: LTU-PB-EX--09/090--SELocal ID: 76202084-4b9a-4ff1-96e7-aa42ead03626OAI: diva2:1023449
Subject / course
Student thesis, at least 30 credits
Educational program
Chemical Engineering, master's level
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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