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Applied and Environmental Soil Science
Volume 2009, Article ID 857640, 6 pages
http://dx.doi.org/10.1155/2009/857640
Research Article

Mobility of Iron-Cyanide Complexes in a Humic Topsoil under Varying Redox Conditions

1Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749 Jena, Germany
2Geographisches Institut, Universität zu Köln, Albertus-Magnus-Platz, 50923 Köln, Germany

Received 8 May 2008; Revised 21 October 2008; Accepted 11 December 2008

Academic Editor: Teodoro Miano

Copyright © 2009 Thilo Rennert and Tim Mansfeldt. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The potentially toxic Fe-CN complexes ferricyanide, , and ferrocyanide, , undergo a variety of redox processes in soil, which affect their mobility. We carried out microcosm experiments with suspensions of a humic topsoil (pH 5.3; 107 g ) to which we added ferricyanide (20 mg ). We varied the redox potential () from −280 to 580 mV by using , and glucose. The decrease of led to decreasing concentrations of Fe-CN complexes and partial reductive dissolution of (hydrous) Fe and Mn oxides. The dynamics of aqueous Fe-CN concentrations was characterized by decreasing concentrations when the pH rose and the dropped. We attribute these dependencies to adsorption on organic surfaces, for which such a pH/ behavior has been shown previously. Adsorption was reversible, because when the pH and changed into the opposite direction, desorption occurred. This study demonstrates the possible impact of soil organic matter on the fate of Fe-CN complexes in soil.