Source:http://linkedlifedata.com/resource/pubmed/id/16852465
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
24
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| pubmed:dateCreated |
2006-7-20
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| pubmed:abstractText |
We have examined the thermodynamics and kinetics of hydroxide (OH-) ions that formed in cages of 12 CaO x 7 Al2O3 (C12A7) with nanoporous structures. It is confirmed using thermogravimetric-evolved gas analyses (TG-EGA) that hydration in C12A7 is mediated by a reaction between an oxide (O2-) ion in the cage and an H2O molecule in the atmosphere to form two OH- ions in the cages. To simply and exactly quantify the OH- content from infrared absorption measurements of OH-stretching band, we propose a method combined with a thermodynamic analysis, allowing the simultaneous determination of the molar extinction coefficient of the OH-band, enthalpy, and entropy for the hydration. Hydration enthalpy in C12A7 is extremely high compared with other oxides and was enhanced by the marked instability of O2- ion in the cage. Consequently, high solubility of OH- ion is retained up to unusually high temperatures. Furthermore, we determined diffusion coefficients of species relevant to the hydration process and demonstrated that inward diffusion of OH- ions is the rate-determining process.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
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| pubmed:month |
Jun
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| pubmed:issn |
1520-6106
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:day |
23
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| pubmed:volume |
109
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
11900-6
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| pubmed:year |
2005
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| pubmed:articleTitle |
Thermodynamics and kinetics of hydroxide ion formation in 12 CaO x 7 Al2O3.
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| pubmed:affiliation |
Frontier Collaborative Research Center, Tokyo Institute of Technology, S2-13, 4259 Nagatsuta, Yokohama 226-8503, Japan. k-hayashi@lucid.msl.titech.ac.jp
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| pubmed:publicationType |
Journal Article
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