Effect of hydroxamate siderophores on Fe release and Pb(II) adsorption by goethite

Author(s): Stephan Krämer, Sing-Foong Cheah, R Zapf, Jing-Jun Xu, Kenneth N. Raymond, Garrison Sposito
Abstract: Hydroxamate siderophores are biologically-synthesized, Fe(III)-specific ligands which are common in soil environments. In this paper, we report an investigation of their adsorption by the iron oxyhydroxide, goethite; their influence on goethite dissolution kinetics; and their ability to affect Pb(II) adsorption by the goethite surface. The siderophores used were desferrioxamine B (DFO-B), a fungal siderophore, and desferrioxamine, D1, an acetyl derivative of DFO-B (DFO-D1). Siderophore adsorption isotherms yielded maximum surface concentrations of 1.5 (DFO-B) or 3.5 (DFO-D1) ?mol/g at pH 6.6, whereas adsorption envelopes showed either cation-like (DFO-B) or ligand-like (DFO-D1) behavior. Above pH 8, the adsorbed concentrations of both siderophores were similar. The dissolution rate of goethite in the presence of 240 ?M DFO-B or DFO-D1 was 0.02 or 0.17 ?mol/g hr, respectively. Comparison of these results with related literature data on the reactions between goethite and acetohydroxamic acid, a monohydroxamate ligand, suggested that the three hydroxamate groups in DFO-D1 coordinate to Fe(III) surface sites relatively independently. The results also demonstrated a significant depleting effect of 240 ?M DFO-B or DFO-D1 on Pb(II) adsorption by goethite at pH > 6.5, but there was no effect of adsorbed Pb(II) on the goethite dissolution rate.
Organisation(s)
External organisation(s): University of California, Berkeley, Nankai University
Journal: Geochimica et Cosmochimica Acta
Volume: 63
Pages: 3003-3008
No. of pages: 6
ISSN: 0016-7037
Publication date: 1999
Peer reviewed: Yes
Austrian Fields of Science 2012: 105904 Environmental research
Portal url: https://ucrisportal.univie.ac.at/en/publications/effect-of-hydroxamate-siderophores-on-fe-release-and-pbii-adsorption-by-goethite(fae2e889-549e-4af1-a9a6-42e0395c52bd).html

Back