T36 Basic and Applied Aspects of Clays and Clay Minerals in Continental Settings (Posters)

Sunday, 9 October 2011
9:00 AM - 6:00 PM
Hall C

DETERMINATION OF SWELLING RATES OF NAu-1 QUASI-CRYSTALS DURING CATION EXCHANGE USING ATOMIC FORCE MICROSCOPY

Paper number: T36-7
Program: Technical Sessions
Time: 9:00 AM – 6:00 PM

Authors

Abstract

In situ observations of the swelling properties of the nontronite clay NAu-1 were carried out via intermittent contact Atomic Force Microscopy (AFM). Using a fluid cell, a sodium saturated sample of NAu-1 was flushed with ultra pure water, allowing osmotic swelling to occur. The system was flushed with 0.5 M KCl solution and changes in swelling were observed in 30- second intervals in real time. Due to the difference in the hydration energy of K+ as compared to Na+, an overall decrease in swelling was observed. However, changes in the d-spacing between different layers within a quasi-crystal were observed to vary from layer to layer, suggesting that mechanical forces also play a role in swelling. With this data, the swelling rates of individual layers can be directly calculated, allowing for a better understanding of the variables that govern the swelling process.