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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-11-25
pubmed:abstractText
Dehydration of a series of homoionic alkali-exchanged montmorillonites is studied at different treatment temperatures by means of thermogravimetric analysis. More specifically, we investigate the last stages of dehydration when the number of adsorbed water molecules corresponds, at maximum, to a monolayer. Weight losses are measured at several constant temperatures as a function of time. Application of Van't Hoff's law yields the dehydration enthalpy. Trends and data similar to those reported from other experimental conditions are found. Comparison with X-ray data and with the dissociation enthalpy of alkali cation/water complexes shows that dehydration of weakly hydrated homoionic alkali montmorillonites results from the competition between opposite energy contributions due to (i) the cation solvation, (ii) the hydration of the silicate interlayer surface, and (iii) the structural swelling. So, depending on the balance between these various energy contributions, different behaviors are observed according to the nature of the alkali cations.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
1095-7103
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
329
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
339-45
pubmed:dateRevised
2009-11-11
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Dehydration enthalpy of alkali-cations-exchanged montmorillonite from thermogravimetric analysis.
pubmed:affiliation
Laboratoire Synthèse et Catalyse, Université Ibn Khaldoun Tiaret, BP 78, 14000 Tiaret, Algeria.
pubmed:publicationType
Journal Article