The dominant mode of binding of aqueous Pb(II) to single crystal (0001) (C-cut) and (1-102) (R-cut) surfaces of a-Fe2O3 has been determined using grazing-incidence x-ray absorption fine structure (GI-XAFS) spectroscopy. Oligomeric Pb(II) complexes were found to bind in inner-sphere modes on both surfaces, which is in contrast with the binding of aqueous Pb(II) on a-Al2O3 (0001) surfaces, where Pb(II) was found in past GI-XAFS studies to bind in a dominantly outer-sphere mode, indicating a significant difference in reactivity of these two surfaces to Pb(II). This difference in reactivity to Pb(II) is explained on the basis of recent crystal truncation rod diffraction studies of the a-Fe2O3 and a-Al2O3 C-cut surfaces in contact with bulk water, which found major structural differences between the surfaces of these two metal oxides.
Revised: April 6, 2004 |
Published: March 2, 2004
Citation
Bargar J., T.P. Trainor, J.P. Fitts, S.A. Chambers, and G.E. Brown. 2004.In Situ Grazing-Incidence Extended X-ray Absorption Fine Structure Study of Pb(II) Chemisorption on Hematite (0001) and (1-102) Surfaces.Langmuir 20, no. 5:1667-1673.PNNL-SA-40145.