VANADIUM(V) ADSORPTION ONTO GOETHITE (α-FEOOH) AT PH 1.5 TO 12: A SURFACE COMPLEXATION MODEL BASED ON AB INITIO MOLECULAR GEOMETRIES AND EXAFS SPECTROSCOPY
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dc.contributor.author | Peacock C.L. | |
dc.contributor.author | Sherman D.M. | |
dc.date.accessioned | 2022-03-23T07:44:08Z | |
dc.date.available | 2022-03-23T07:44:08Z | |
dc.date.issued | 2004 | |
dc.identifier | https://www.elibrary.ru/item.asp?id=12090611 | |
dc.identifier.citation | Geochimica et Cosmochimica Acta, 2004, 68, 8, 1723-1733 | |
dc.identifier.issn | 0016-7037 | |
dc.identifier.uri | https://repository.geologyscience.ru/handle/123456789/36583 | |
dc.description.abstract | We measured the adsorption of V(V) onto goethite (α-FeOOH) under oxic (PO2 = 0.2 bar) atmospheric conditions. EXAFS spectra show that V(V) adsorbs by forming inner-sphere complexes as VO2(OH)2 and VO3(OH). We predicted the relative energies and geometries of VO2(O, OH)2-FeOOH surface complexes using ab initio calculations of the geometries and energetics of analogue Fe2(OH)2(H2O)6O2VO2(O, OH)2 clusters. The bidentate corner-sharing complex is predicted to be substantially (57 kJ/mol) favoured energetically over the hypothetical edge-sharing bidentate complex. Fitting the EXAFS spectra using multiple scattering shows that only the bidentate corner-sharing complex is present with Fe-V and V-O distances in good agreement with those predicted. We find it important to include multiple scattering in the fits of our EXAFS data otherwise spurious V-Fe distances near 2.8 Å result which may be incorrectly attributed to edge-sharing complexes. We find no evidence for monodentate complexes; this agrees with predicted high energies of such complexes. Having identified the Fe2O2V(OH)2+ and Fe2O2VO(OH)0 surface complexes, we are able to fit the experimental vanadium(V) adsorption data to the reactions and We also determined the first acid dissociation constant of the Fe2O2VO2H2+ surface complex.Fits of sorption edges to surface complexation models are ambiguous. This is one of the first studies to provide a surface complexation model of sorption edges that is consistent with both spectroscopic and quantum mechanical constraints. | |
dc.subject | goethite | |
dc.title | VANADIUM(V) ADSORPTION ONTO GOETHITE (α-FEOOH) AT PH 1.5 TO 12: A SURFACE COMPLEXATION MODEL BASED ON AB INITIO MOLECULAR GEOMETRIES AND EXAFS SPECTROSCOPY | |
dc.type | Статья |
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