XAFS Characterization of Copper in Model Aqueous Systems of Humic Acid and Illite

D. Hesterberg; D.E. Sayers; W. Zhou; W.P. Robarge; G.M. Plummer

doi:doi:10.1051/jp4:1997253

Numéro		J. Phys. IV France Volume 7, Numéro C2, Avril 1997 Proceedings of the 9th International Conference on X-Ray Absorption Fine Structure


Page(s)		C2-833 - C2-834
DOI		https://doi.org/10.1051/jp4:1997253

Proceedings of the 9th International Conference on X-Ray Absorption Fine Structure

J. Phys. IV France 7 (1997) C2-833-C2-834
DOI: 10.1051/jp4:1997253

XAFS Characterization of Copper in Model Aqueous Systems of Humic Acid and Illite

D. Hesterberg¹, D.E. Sayers², W. Zhou², W.P. Robarge¹ and G.M. Plummer²

¹ Department of Soil Science, Box 7619, North Carolina State University, Raleigh NC 27695, U.S.A.
² Department of Physics, Box 7518, North Carolina State University, Raleigh NC 27695, U.S.A.

Abstract
Adsorption of heavy metals at mineral surfaces and complexation with reactive organic-matter functional groups are important processes regulating the solubility and fate of soil contaminants. To determine the nature of Cu(II) bonding in complex clay-organic systems, XAFS analyses were conducted on aqueous suspensions containing Cu(II) in various forms : (i) complexed with soil humic acid (HA) at various HA : Cu ratios, (ii) bound to illite, or (iii) bound in a mixture of illite and HA. Spectral features for Cu bound to HA did not depend significantly on the HA : Cu ratio, and average first-shell Cu-O bond lengths were consistently shorter than for the Cu-illite systems. In the mixed clay-organic suspension, Cu bonding was more characteristic to that of Cu bound with HA.