Development of an evolved gas analysis instrument and the investigation of a stepped isothermal method for the study of water desorption from zeolites

Date
2003-08
Authors
Covington, Michael Neal
Contributor
Advisor
Andermann, George
Department
Chemistry
Instructor
Depositor
Speaker
Researcher
Consultant
Interviewer
Annotator
Journal Title
Journal ISSN
Volume Title
Publisher
University of Hawaii at Manoa
Volume
Number/Issue
Starting Page
Ending Page
Alternative Title
Abstract
A stepped isothermal pressure change method for the investigation of water desorption from zeolites has been developed. Stepped isothermal evolved gas analysis (SI-EGA) utilizes static methods, in a unique way, to determine kinetic data. This method produces isothermal kinetic data. The problems associated with dynamic methods are reduced by the use of an isothermal method. Zeolites NaY, NaX, and CaX have been investigated to determine if the SI-EGA method yields reliable kinetic data. This method consists of multiple expansions into vacuum carried out through a temperature range. The results of the SI-EGA experiments show water desorbing from zeolites NaY, NaX, and CaX with apparent energies of desorption (Ea) of 34 ± 3 kJ/mol, 16.9 ± 0.4 kJ/mol, and 40 ± 1 kJ/mol respectively. The results also give preexponential factors (Aa) of 156 ± 121 sec-1, 0.5 ± 0.1 sec-1, and 744 ± 295 sec-1 for zeolites NaY, NaX, and CaX, respectively. The results confirm that the SI-EGA method produces reliable kinetic data for water desorption from zeolites. A refinement of the SI-EGA method could be useful for the investigation of desorption from microporous solids.
Description
xi, 110 leaves
Keywords
Citation
Extent
Format
Geographic Location
Time Period
Related To
Theses for the degree of Master of Science (University of Hawaii at Manoa). Chemistry; no. 3792
Table of Contents
Rights
All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Rights Holder
Local Contexts
Collections
Email libraryada-l@lists.hawaii.edu if you need this content in ADA-compliant format.