AVS 50th International Symposium
    Technology for Sustainability Thursday Sessions
       Session AT-ThA

Paper AT-ThA3
Environmental Transformation of Uranium-Organic Complexes: Implications for Transport and Remediation

Thursday, November 6, 2003, 2:40 pm, Room 320

Session: Science and Technology Related to Global Effects: Emissions, Climate, and Transport
Presenter: C.W. Eng, State University of New York at Stony Brook
Authors: C.W. Eng, State University of New York at Stony Brook
G.P. Halada, State University of New York at Stony Brook
A.J. Francis, Brookhaven National Laboratory
C.J. Dodge, Brookhaven National Laboratory
Correspondent: Click to Email
Transportation and fate of uranium are fundamentally affected by the nature of their association with pervasive organic environmental molecular constituents resulting from natural or man-made sources. Understanding the role of organic ligands and the transformation of these complexes is essential to the development and optimization of remediation technologies. For example, u-organic complexation adversely affect the ability of certain bacteria to reduce soluble uranium (U(VI)) to a more insoluble form (U(IV)).@footnote 1@ Organic ligands can coordinate with uranium in aqueous solution and perhaps decrease the effectiveness of the ZVI. In literature, the fate of the uranium and organic ligands are not fully elucidated in these systems. Our research provides fundamental information about the structure and transformation of uranium-organic complexes through electrochemical and spectroscopic analyses. The organic ligands chosen in this study will be relatively simple molecules (e.g. salicylic acid, catechol), which are used as analogs for more complex molecules found in the environment. The objectives of this work include a) characterization of the uranium and organic ligands; b) the electrochemical behavior of u-organic complexes; c) the relative stability and mobility of the uranium-organic complexes; and d) the ultimate fate of the uranium and ligands. X-ray Photoelectron Spectroscopy , laboratory and synchrotron-based Fourier Transform Infrared analysis, and in-situ electrochemical experiments will be combined with synchrotron-based X-ray Absorption and Raman spectroscopies. The resulting structural and molecular spectroscopic data is then used to generate computational molecular models, so that molecular orbital structures of complexes can be related to both stability and reactivity of uranium-organic ligands. @FootnoteText@@footnote 1@ Biotransformation of uranium and other actinides in radioactive wastes, A.J. Francis, Journal of Alloys and Compounds (1998), 271-273, 78-84.