Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 8: Oxides and insulators: Adsorption I

O 8.6: Talk

Monday, March 14, 2011, 12:30–12:45, WIL C307

Sorption of Arsenic Complexes at FeOOH Surfaces from First Principles — •Katrin Otte, Wolfgang W. Schmahl, and Rossitza Pentcheva — Section Crystallography, Dept. of Earth and Environmental Sciences, University of Munich

Iron oxyhydroxides (FeOOH) possess high surface areas and are of relevance for various processes in nature and technology as cycling and retention of contaminants, e.g. for water treatment purposes. [1] Using density functional theory (DFT), we investigate the adsorption affinities of the FeOOH polymorphs goethite (α), akaganeite (β), and lepidocrocite (γ) to heavy metal complexes. The knowledge of the clean surfaces goethite(101), akaganeite(100), and lepidocrocite(010) is a starting point to address those. The GGA+U calculations reveal that the termination impacts the oxidation state of the topmost iron, providing a possibility to tune the catalytic activity. The energetics and bonding mechanisms of contaminants in different adsorption geometries on the surfaces are analyzed.

Funding by the BMBF programme Geotechnologies and Elitenetzwerk Bayern is acknowledged.

[1] R. M. Cornell and U. Schwertmann, The Iron Oxides (Wiley, Weinheim, 2001).