Publication Date

2000

Document Type

Dissertation/Thesis

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Chemistry and Biochemistry

LCSH

Uranium compounds; Cations; Ionic solutions; Electrolytes--Conductivity; Electrochemistry

Abstract

The interface between two immiscible electrolytic solutions (ITIES) has been of electrochemical interest for most of this century. There has been much research on this topic over the last 25 years, and the study of ionic transport across the ITIES is now a common practice. Yet in spite of this, little is known of the physical nature of the interface. Many methods have been developed in that time to examine this interface and new ones are constantly being tried. The Advanced Photon Source (APS) facility in Argonne National Laboratory specializes in the utilization of high-energy and high-flux Xrays for surface and interface imaging. A method for study of the ITIES on an atomic-scale resolution involving X-rays can be developed using the APS facility. In order to visualize the interface it is necessary that the boundary possesses a high contrast for the used radiation, i.e., the cross-section of the nuclei in either phase has to differ significantly. To perform electrochemistry on this interface it would be desirable to use an ion that transports across the interface and possesses a large crosssection for X-ray absorption. Uranyl cation would have the necessary cross-section and the needed transport properties if it could be induced electrochemically to cross the interface within the potential boundaries defined by the electrochemical system. In this thesis, the behavior of uranyl at the ITIES is studied in several ways. Uranyl is too hydrophilic and it cannot be transported alone. Another water-soluble uranium compound (UCU) also proves unsuccessful. In such a case, transport facilitated by complexation is an option. It has been performed with various species to attempt transport within the confines of the potential window. The use of phosphine oxide shows no significant improvement over virginal transport. Heavy-weight poly(ethylene) glycols show current flow when complexed with uranyl but are subject to interference by supporting electrolytes. Polyvinylpyrrolidone (PVP) shows current flow with uranyl only. This complex provides reproducible current peak characteristics in a voltammetric study and defines a reversible, diffusion-controlled process. Using this complex at the APS facility at Argonne will allow imaging of ionic transport across an interface in the future.

Comments

Includes bibliographical references (pages [177]-179)

Extent

xii, 179 pages

Language

eng

Publisher

Northern Illinois University

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In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

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Text

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