Sorption of desferrioxamine siderophores to a smectite clay

GEOC 66

E. A. Haack, ehaack@nd.edu1, Cliff T. Johnston, clays@purdue.edu2, and Patricia A. Maurice, pmaurice@nd.edu1. (1) Department of Civil Engineering and Geological Sciences, University of Notre Dame, South Bend, IN 46556, (2) Crop, Soil and Environmental Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907
This study examined the nature of the interaction(s) between smectite clay and desferrioxamine siderophores (DFO-B and DFO-D) using batch adsorption experiments together with structural (XRD) and spectroscopic analysis (FTIR). Both a neutral (DFO-D) and a positively charged siderophore (DFO-B+) strongly sorbed to a Na-exchanged smectite at pH 5.5. Sorption of the siderophores in the interlayer with structure oriented parallel to the siloxane surface is indicated by the basal spacings (13.6 and 17.3 Å). Spectral changes in the position of the structural OH-bending vibrations of the clay, and the band positions assigned to δNH3+ for DFO-B+ sorbed samples provided insight into the specific interaction between the sorbed siderophore and the clay surface. Interpretation of changes to the position, absorption and shape of the Amide-I and -II bands with increased sorption indicate that interactions between the siderophore and the clay surface and/or exchangeable cation occur largely through the carbonyl groups.
 

Physical Chemistry of Soil and Aquifer Systems: A Symposium in Honor of Garrison Sposito
8:15 AM-11:55 AM, Monday, 11 September 2006 Moscone Center -- Room 256, Oral

Division of Geochemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006