GEOC 176 |
| Courtney R. Usher1, Curtis Cleveland1, Daniel R. Strongin1, and Martin A. A. Schoonen2. (1) Department of Chemistry, Temple University, 13th and Norris Streets, Philadelphia, PA 19122, (2) Department of Geosciences, The State University of New York at Stony Brook, Stony Brook, NY 11794-2100 |
| The oxidation of pyrite (FeS2) was examined using horizontal attenuated total reflectance Fourier transform infrared spectroscopy (HATR-FTIR) in order to elucidate the possible source of oxygen atoms in the product formed in the reaction of FeS2 with water and dissolved molecular oxygen. In the presence of oxygenated H218O water, infrared bands corresponding to sulfate are observed to have shifted with respect to the bands that form when oxygenated H216O is present. The isotopic shift is consistent with 18O incorporation from water molecules in the sulfate product. In contrast, infrared bands associated with the iron oxyhydroxide product are not affected when H218O is used as the reactant. This result suggests that the iron oxide product consists of oxygen atoms derived primarily from dissolved molecular oxygen. Additionally, it was shown by HATR-FTIR using gaseous reactants that the oxidation reaction to form sulfate and iron oxides is enhanced when both gaseous H2O and O2 are present versus when only gaseous H2O or O2 is present. |
|
Vibrational Spectroscopy in the Earth and Environmental Sciences
8:00 AM-11:40 AM, Thursday, April 1, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |