ARS | Publication request: SOFT X-RAY SPECTROMICROSCOPY STUDIES ON AQUEOUS CLAY- AND SOIL SUSPENSIONS

Submitted to: National Synchrotron Light Source Annual Report
Publication Type: Abstract Only
Publication Acceptance Date: December 31, 1997
Publication Date: N/A

Technical Abstract: In clay and soil science, structural properties as well as surface reactions and many other processes of interest depend on water, solutions, or other liquids surrounding the actual sample. In order to start different studies on these fields, a wet specimen cell matched to the special requirements of the X1-A Scanning Transmission X-Ray Microscope has sbeen designed. The wet cell consists of two 100 nm thick silicon nitride windows that are pulled together by surface tension forces and form a suspension/solution layer of a few micron thickness, which allows detection of soft x-rays in transmission. First results show the capability of the cell to be used to take XANES spectra and images from liquid and aqueous samples with sub 100 nm spatial resolution. This work was supported by a fellowship for Ph.D.-research studies (UN) from German Academics Exchange Service (DAAD) and by the Office of Biological and Environmental Research, U.S. DoE under contract DE-FG02-89ER60858. We obtained C-XANES spectra of paraffin oil (bulk sample) and hydrated polyacrylamide macromolecules, including a fully hydrated aggregate consisting of 2-0.2 um kaolinite clay particles and polyacrylamide (PAM), an organic flocculant, suspended in an aqueous solution of 0.01M CaCl*2. (The kaolinite is the Clay Minerals Society source clay KGa-1. Clay content is 10 mg/mL, PAM content is 0.005 mg/mL.) Figures were included with the original abstract.