Determining copper and lead binding in Larrea tridentata through chemical modification and X-ray absorption spectroscopy
- Univ. of Texas, El Paso, TX (United States). Dept. of Chemistry
- Stanford Synchrotron Radiation Lab., Menlo Park, CA (United States)
Metal contamination in soils has become a widespread problem. Emerging technologies, such as phytoremediation, may offer low cost cleanup methods. The authors have identified a desert plant, Larrea tridentata (creosote bush), which naturally grows and uptakes copper and lead from a contaminated area near a smelting operation. They determined, through chemical modification of carboxyl groups with methanol, that these functional groups may be responsible for a portion of copper(II) binding. In contrast, lead binding was minimally affected by modification of carboxyl groups. X-ray absorption spectroscopy studies conducted at Stanford Synchrotron Radiation Laboratory (SSRL) further support copper binding to oxygen-coordinated ligands and also imply that the binding is not solely due to phytochelatins. The EXAFS data indicate the presence of both Cu-O and Cu-S back scatters, no short Cu-Cu interactions, but with significant Cu-Cu back scattering at 3.7 {angstrom} (unlike phytochelatins with predominantly Cu-S coordination and short Cu-Cu interactions at 2.7 {angstrom}). Cu EXAFS of roots and leaves also vary depending on the level of heavy metal contamination in the environment from which the various creosote samples were obtained. In contrast, Pb XANES data of roots and leaves of creosote collected from different contaminated sites indicate no difference in valence states or ligand coordination.
- Sponsoring Organization:
- National Insts. of Health, Bethesda, MD (United States); USDOE, Washington, DC (United States)
- OSTI ID:
- 585723
- Report Number(s):
- CONF-9705104-; TRN: IM9810%%2
- Resource Relation:
- Conference: 12. Annual conference on hazardous waste remediation, Kansas City, MO (United States), 20-22 May 1997; Other Information: PBD: 1997; Related Information: Is Part Of Proceedings of the 12. annual conference on hazardous waste research. Building partnerships for innovative technologies; Erickson, L.E.; Rankin, M.M.; Grant, S.C.; McDonald, J.P. [eds.]; PB: 586 p.
- Country of Publication:
- United States
- Language:
- English
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