Synchrotron x-ray spectroscopic studies of metal ion chemisorption reactions at oxide-water interfaces
- Stanford Univ., CA (United States)
Macroscopic adsorption isotherm measurements provide useful data on aqueous metal ion uptake as a function of solution pH and ionic strength; however, they cannot quantity reaction stoichiometries. In contrast, synchrotron-based X-ray absorption spectroscopy measurements on metal ions chemisorbed at oxide-water interfaces can provide unique structural and compositional information on the first-and second-neighbor environment of such ions and their mode of surface binding (inner-sphere vs. outer-sphere complexation, precipitation, absorption). When multi-element array detectors are utilized to measure the fluorescent X-ray yield of a selected element as a function of X-ray energy, X-ray absorption fine structure (XAFS) spectra of chemisorbed metal species at less than monolayer coverage can be obtained and quantitatively analyzed. Such measurements can be made on metal species chemisorbed on high surface area powdered sorbents or on single crystal sorbents in grazing-incidence mode. Examples of recent XAFS studies of Co(II) and Pb(II) sorption at alumina-water interfaces and of Cr(VI) reduction at magnetite-water interfaces will be presented. The information from such studies can be used to constrain macroscopic models of uptake of environmental interest.
- OSTI ID:
- 466500
- Report Number(s):
- CONF-951017-; TRN: 96:005999-0032
- Resource Relation:
- Conference: 22. annual conference of the Federation of Analytical Chemistry and Spectroscopy Societies, Cincinnati, OH (United States), 15-20 Oct 1995; Other Information: PBD: 1995; Related Information: Is Part Of FACSS XXII - the 22nd annual conference of the Federation of Analytical Chemistry and Spectroscopy Societies; PB: 285 p.
- Country of Publication:
- United States
- Language:
- English
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