ISSN:
1572-879X
Schlagwort(e):
Montmorillonite
;
clay
;
charge reduction
;
cation migration
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract Controlled calcination of ion-exchanged Texas montmorillonite leads to layer charge reduction. Detailed chemical analyses of both exchangeable and unexchangeable metal species lead to the conclusion that, in complete contrast to the situation with Wyoming bentonite, Ni2+, Co2+ and Zn2+ are all capable of migrating from the interlamellar space into the octahedral region of the sheets where they are (i) isomorphously exchanged for Mg2+, and to a proportionately smaller extent, for Fe2+, (ii) trapped in the octahedral vacancies. In addition, they are converted to unexchangeable species on the interlamellar sheet surfaces by high temperature hydrolysis leading to hydroxide or oxide formation. It is suggested that protons within the octahedral region are bound as -OH+ 2rather than simply physically trapped.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00769442
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