Topotactic cation exchange in transformed micas under hydrothermal conditions
Cho, Yunchul (The Pennsylvania State University. Department of Crop and Soil Sciences)
Komarneni, Sridhar (The Pennsylvania State University. Department of Crop and Soil Sciences)

Data:	2007
Resum:	The formation of hydroxylated phases was investigated using K-depleted biotite (Na-biotite) and K-depleted muscovite (Na-muscovite) under hydrothermal treatment with alkali (Li, K, NH , Rb and Cs), alkaline earth (Mg, Ca, Sr and Ba), and aluminum (Al) cations at 200°C for 1 and/or 3 days. The K-depleted biotite treated with alkali cations produced anhydrous hydroxylated phases, while the K-depleted muscovite did not significantly exchange alkali cations but dehydrated to form Na-muscovite in all cases. The alkaline earth cations, however, produced hydrous hydroxylated phases with both K-depleted micas. The degree of hydration energy of cations and the charge density of micas were found to influence the formation of anhydrous and hydrous phases from the K-depleted micas. This type of topotactic cation exchange potentially could be used for fixation and immobilization of radioactive species such as Cs, Sr, Ra, etc. in the transformed micas. The K-depleted biotite and muscovite treated with Al were transformed to hydroxy-Al interlayered vermiculites (HIV) because of hydrolysis and polymerization of Al. These HIV phases could also serve as useful adsorbents for soil and groundwater contaminants.
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Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Hydrothermal Treatment ; Hydroxy-Al Interlayered Vermiculite (HIV) ; K-depleted Biotite ; K-depleted Muscovite ; Topotactic Cation Exchange ; Transformation
Publicat a:	Clays and Clay Minerals, Vol. 55, Núm. 6 (2007) , p. 593-598, ISSN 1552-8367

DOI: 10.1346/CCMN.2007.0550606

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