Journal article

Evaluation of Gibbs Energy of Dioxouranium Transfer at an Electrified Liquid vertical bar Liquid Interface Supported on a Microhole

Herein is reported the determination of the Gibbs energy of dioxouranium (UO22+) transfer across an interface between two immiscible electrolytic solutions (ITIES), water and 1,2-dichloroethane, that was supported at a 25 mu m diameter microhole, by means of linear sweep voltammetry. Through the use of minimal to no supporting electrolyte, this technique is able to observe ion transfer (IT) of extremely hydrophilic ions voltammetrically. As the applied potential in the aqueous phase became increasingly positive the UO22+ ions were driven into the organic phase resulting in IT. The standard transfer potential, Delta(w)(o)phi(o)' was determined to be 0.865 V through a novel curve fitting methodology applied directly to the voltammogram. The Gibbs energy of transfer was calculated to be 167 kJ.mol(-1). Additionally, the kinetics of IT was explored using a Butler-Volmer model through finite element analysis, whereby the voltammetric current response owning to migration effects in the experimental CVs was approximated in the overlaid, simulated CVs using slow reaction kinetics.

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