Hydration enthalpy measurement and evaluation as heat exchangers of allophane and imogolite

Citation
M. Suzuki et al., Hydration enthalpy measurement and evaluation as heat exchangers of allophane and imogolite, J CERAM S J, 109(8), 2001, pp. 681-685
Citations number
20
Language
CHINESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
JOURNAL OF THE CERAMIC SOCIETY OF JAPAN
ISSN journal
0914-5400 → ACNP
Volume
109
Issue
8
Year of publication
2001
Pages
681 - 685
Database
ISI
SICI code
0914-5400(200108)109:8<681:HEMAEA>2.0.ZU;2-0
Abstract
The hydration enthalpies of allophane and imogolite have been measured by m eans of the adiabatic vapor absorption calorimeter. The hydration enthalpy (DeltaH(h)) of allophane and imogolite were -63.2 kJ/mol and -59.8 kJ/mol, respectively, which were almost the same as those of a zeolite group. The t otal heat of hydration (Q) of allophane was 409 kJ/kg at the dehydration te mperature of 80 degreesC, and was 1.5 times larger than that of the Mg-A ty pe zeolite, The Q-value of imogolite was 405 kJ/kg at the dehydration tempe rature of 40 degreesC, and was 2.2 times larger than that of the Mg-A type zeolite. Allophane and imogolite are thus characterized by larger Q-values than that of Mg-A type zeolite when they are dehydrated at low temperature below 100 degreesC. This shows that allophane and imogolite are suitable fo r heat exchange absorbents of zeolite-water heat pumps for low temperature heat sources.