Clays and Clay Minerals, Vol. 55, No. 4, 339–347, 2007.
Loading...
Authors
Aldushin, Kirill
Jordan, Guntram
Aldushina, Elena
Schmahl, Wolfgang W.
Issue Date
2007
Type
Article
Language
Keywords
Periodicals , Geology , Alkylammonium , Atomic Force Microscopy , Clays , Cation Exchange , Diffusion , Mica , Organic Ions , Phyllosilicates , Surface Alteration , Swelling
Alternative Title
On The Kinetics Of Ion Exchange In Phlogopite - An In Situ Afm Study
Abstract
The kinetics of cation exchange in phlogopite have been studied in situ by hydrothermal atomic force microscopy (HAFM). The exchange of interlayer K by octylammonium ions caused an increase in the interlayer distance and the formation of reaction fronts which can be locally resolved by AFM. The observed reaction fronts revealed substantial variations in their propagation rates - even within single interlayers. This observed variability in interlayer reactivity could mainly be attributed to chemical and structural inhomogeneities of the samples. A quantitative evaluation of the front propagation at representative sites yielded a diffusion coefficient of the K+ exchange by octylammonium of 1.2A0.6610-11 cm2/s assuming negligible transport normal to the layers. The reverse reaction, i.e. t he exchange of organic ions by K+, resulted in a retreat of the reaction fronts and a general restoration of the original morphological state. However, indications of structural alterations and areas with trapped octylammonium ions were found.
Description
Clays and Clay Minerals, Vol. 55, No. 4, 339–347, 2007. On The Kinetics Of Ion Exchange In Phlogopite - An In Situ Afm Study. Kirill Aldushin; Guntram Jordan; Elena Aldushina; Wolfgang W. Schmahl. DOI: 10.1346/CCMN.2007.0550401. Copyright © 2007, The Clay Minerals Society
Citation
Clays and Clay Minerals, Vol. 55, No. 4, 339–347, 2007.
Publisher
The Clay Minerals Society
License
Copyright © 2006-2018, The Clay Minerals Society