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Characterization of adsorption sites on aggregate soil samples using synchrotron X-ray computerized microtomography
Susan J Altman1, Mark L Rivers, Marissa D Reno
1Geohydrology Department, Sandia National Laboratories, Albuquerque, New Mexico 87185-0735, USA. sjaltma@sandia.gov
Environmental Science & Technology
|May 12, 2005
Summary
Synchrotron X-ray microtomography quantified iron content in soil aggregates, revealing its link to adsorptive properties. This method helps understand contaminant transport in soils.
Area of Science:
- Geochemistry
- Environmental Science
- Materials Science
Background:
- Soil aggregate properties influence contaminant transport.
- Iron oxides are key components affecting soil adsorption.
- Advanced imaging techniques are needed to characterize soil microstructures.
Purpose of the Study:
- To evaluate the adsorptive properties of soil aggregates using synchrotron-source X-ray computerized microtomography (CMT).
- To establish a relationship between iron content and adsorptive capacity in soil samples.
- To visualize and quantify cesium adsorption on soil intergranular material.
Main Methods:
- Synchrotron-source X-ray computerized microtomography (CMT) was employed.
- Mineral standards with known iron content were imaged to establish a calibration curve.
- Absorption edge difference imaging was used to visualize cesium adsorption.
Main Results:
- A linear relationship was found between the mean mass attenuation coefficient and the mass fraction of iron.
- Mass fractions of iron and iron oxyhydroxide in intergranular material were quantified.
- Cesium was visualized on the intergranular material, indicating adsorption and potential exchange reactions.
Conclusions:
- CMT is effective for characterizing iron content and adsorptive properties of soil aggregates.
- Quantification of iron and iron oxyhydroxide is crucial for understanding soil behavior.
- This research provides valuable data for developing and parametrizing soil transport models.