GEOC 43 |
| Young Jae Lee1, E.J. Elzinga2, and R.J. Reeder2. (1) Department of Geosciences, SUNY Stony Brook, Stony Brook, NY 11794-2100, (2) Department of Geosciences, State University of New York at Stony Brook, Stony Brook, NY 11794-2100 |
| Zn(II) sorption on hydroxyapatite was studied as a function of pH and Zn(II) concentration, using a combination of batch uptake experiments and extended X-ray absorption fine structure (EXAFS) spectroscopy. The batch sorption data indicate that Zn(II) sorption increases with increasing pH and dissolved Zn(II) concentration. Sorption isotherms at three different pH values (5, 7 and 9) show that Zn(II) uptake reaches a plateau before a sharp increase in Zn(II) removal, suggesting precipitation. EXAFS spectra confirm that Zn(II) adsorption occurs at low concentrations, and precipitation at high Zn(II) concentration. EXAFS also shows that Zn(II) forms inner-sphere adsorption complexes with tetrahedral coordination at the hydroxyapatite surface. The macroscopic and spectroscopic results indicate that Zn sorption complexes are dependent on reaction conditions. |
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Chemistry of Metals in Terrestrial and Aquatic Systems
1:30 PM-5:10 PM, Monday, March 29, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |