GEOC 38 |
| Lia F. Brodnax and Wolfgang H Runde. C-INC, Los Alamos National Laboratory, MS J-514, Los Alamos, NM 87544 |
| In order to improve transport modeling capabilities we are investigating the interactions between aqueous metal contaminants and mineral oxides. Using micro-calorimetry, we have determined the heat of reaction (DH) of heavy metals, lanthanides, and uranyl with silica at 25°C, in the pH region 4-7. The different thermodynamic and kinetic behavior observed between systems provides clues to the different adsorption mechanisms occurring. This represents some of the first thermodynamic data measured for the surface reaction of metal cations with an oxide mineral in an aqueous matrix. By understanding the nature of the surface complex, this fundamental information enables us to describe the interfacial chemistry of metal cations for a wide range of conditions. We will present the energetics of the surface reactions of Cu(II), Sm(III), and U(VI) and compare the measured enthalpies with spectroscopic information on the nature of solution and surface complexes. |
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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 |