GEOC 143 |
| Louise J. Criscenti and Randall T. Cygan. Geochemistry Department, Sandia National Laboratories, Albuquerque, NM 87185-0750 |
| Molecular dynamics simulations were performed to examine the adsorption of lead on a neutral gibbsite surface from an aqueous NaCl solution. A slab model of the hydroxylated basal surface (26Å x 20Å x 18Å) of gibbsite with a 30Å water layer was used to represent this system. Two Na+ and two Cl- ions were added to represent a 0.2M NaCl solution. In a 150 ps simulation, one Cl- and one Na+ ion adsorb to gibbsite as an inner-sphere and outer-sphere complex respectively. Calculations with 2 Na+, 1 Pb2+, and 4 Cl- ions suggest that Cl- and Na+ may adsorb as an ion pair. Three Cl- ions interact with Pb2+ in bulk solution for this case. Initial results suggest that Pb2+ is strongly attracted to Cl- in aqueous solution at these concentrations (0.2M NaCl, 0.1M PbCl2), and will only adsorb to the gibbsite surface in coordination with a Cl- ion. |
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Interfacial Phenomena: Linking Atomistic and Macroscopic Properties
8:05 AM-11:30 AM, Wednesday, March 31, 2004 Marriott -- Marquis NW, Oral
Division of Geochemistry |