Contaminant-Organic Complexes, Their Structure and Energetics in Surface Decontamination Processes
There are many compounds that are naturally occurring biodegradable organic chelates (siderophores) and appear to be more effective at oxide dissolution and actinide complexation than ethylenediaminetetraacetic acid (EDTA) or other organic acids currently used in decontamination processes. These chelates bind hard acids [Fe(III) and actinides(IV)] with extraordinarily high affinities. For example, the binding constant for the siderophore enterobactin with iron is about 1050, and its binding constant for Pu(IV) is estimated to be as high. Hence, this project is investigating the efficacy of using siderophores (or siderophore-like chelates) as decontamination agents of metal surfaces. The specific goals of this project are as follows: (1) To develop an understanding of the interactions between siderophores (and their functional moieties), Fe and actinide oxides, their surface chemical properties that foster their dissolution and the conditions that maximize that dissolution. (2) To develop the computational tools necessary to predict the reactivity of different siderophore functional groups toward oxide dissolution and actinide (IV) solubilization. (3) To identify likely candidate chelates for use in decontamination processes. To meet these objectives, the project combines x-ray absorption spectroscopy (XAS) and computational chemistry to provide basic information on the structure and bonding of siderophore functional groups to metal (Fe and U) oxide specimens common to corrosion products and scales on carbon steel and stainless steel encountered in DOE facilities. The project explores fundamental scientific aspects of oxide mineral surface chemistry and dissolution related to chelate-induced solubilization. The spectroscopic and computational aspects of this project are complemented by macroscopic dissolution and solubilization studies of oxides and associated contaminants. From this combination of molecular, macroscopic, and computational studies, structure-function and structure-reactivity relationships will be developed. These tasks are centered on investigative themes: (1) macroscopic dissolution studies (C. Ainsworth, PNNL), (2) optical spectroscopy (C. Ainsworth [PNNL]), (3) x-ray absorption spectroscopy (XAS) (S. Traina [OSU] and S. Myneni [LBNL]), and (4) computational chemistry (B. Hay [PNNL]).
- Research Organization:
- Pacific Northwest National Laboratory, Richland, WA; Lawrence Berkeley National Laboratory, Berkeley, CA; Ohio State University, Columbus, OH (US)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM) (US)
- DOE Contract Number:
- FG07-98ER14926
- OSTI ID:
- 831221
- Report Number(s):
- EMSP-64947-2000; R&D Project: EMSP 64947; TRN: US200430%%296
- Resource Relation:
- Other Information: PBD: 1 Jun 2000
- Country of Publication:
- United States
- Language:
- English
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Contaminant-Organic Complexes: Their Structure and Energetics in Surface Decontamination Processes
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Related Subjects
54 ENVIRONMENTAL SCIENCES
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
ACTINIDES
BONDING
CARBON STEELS
CHELATES
CHEMICAL PROPERTIES
CHEMISTRY
CORROSION PRODUCTS
DECONTAMINATION
DISSOLUTION
EDTA
FUNCTIONALS
IRON
ORGANIC ACIDS
OXIDE MINERALS
OXIDES
SPECTROSCOPY
STAINLESS STEELS