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Surface complexation studied via combined grazing-incidence EXAFS and surface diffraction: Arsenate on hematite (0001) and (10-12)

Analytical and Bioanalytical Chemistry

By:
, , , , , , , and
DOI: 10.1007/s00216-005-3393-z

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Abstract

X-ray diffraction [crystal-truncation-rod (CTR)] studies of the surface structure of moisture-equilibrated hematite reveal sites for complexation not present on the bulk oxygen-terminated surface, and impose constraints on the types of inner-sphere sorption topologies. We have used this improved model of the hematite surface to analyze grazing-incidence EXAFS results for arsenate sorption on the c(0001) and r(10-12) surfaces measured in two electric vector polarizations. This work shows that the reconfiguration of the surface under moist conditions is responsible for an increased adsorption density of arsenate complexes on the (0001) surface relative to predicted ideal termination, and an abundance of "edge-sharing" bidentate complexes on both studied surfaces. We consider possible limitations on combining the methods due to differing surface sensitivities, and discuss further analysis possibilities using both methods. ?? Springer-Verlag 2005.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Surface complexation studied via combined grazing-incidence EXAFS and surface diffraction: Arsenate on hematite (0001) and (10-12)
Series title:
Analytical and Bioanalytical Chemistry
DOI:
10.1007/s00216-005-3393-z
Volume
383
Issue:
1
Year Published:
2005
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Analytical and Bioanalytical Chemistry
First page:
12
Last page:
27
Number of Pages:
16