Modeling metal-glyphosate complexation in solution and at the metal (hydr)oxide-solution interface

GEOC 82

Caroline Jonsson, caroline.jonsson@chem.umu.se, John S. Loring, john.loring@chem.umu.se, Per Persson, per.persson@chem.umu.se, and Staffan Sjöberg, staffan.sjoberg@chem.umu.se. Department of Chemistry, Umeå University, Inorganic Chemistry, SE-90187 Umeå, Sweden
Glyphosate (N-(phosphonomethyl) glycine, PMG) is a widely used herbicide due to its high activity, low toxicity to animals and short residence time in soil. Glyphosate has a relatively low solubility in water and has a zwitterion structure depending on pH. Metal ions take part in the adsorption process of glyphosate to colloidal fractions and to understand the processes that occur in the environment it is important to examine the role of the solid-water interface and its interactions with the aqueous phase. Glyphosate has been studied with respect to its complexation with copper(II) and cadmium(II) in aqueous solution but also its adsorption onto the goethite (alpha-FeOOH) surface, in the absence or presence of these metals. Data obtained from potentiometric titrations, batch experiments, FT-IR, EXAFS and XPS measurements have been interpreted in terms of surface complexation models.
 

Physical Chemistry of Soil and Aquifer Systems: A Symposium in Honor of Garrison Sposito
1:30 PM-5:10 PM, Monday, 11 September 2006 Moscone Center -- Room 256, Oral

Division of Geochemistry

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