Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (08): 1705-1711.doi: 10.3866/PKU.WHXB201306043

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Electrochemical Behavior of the System of Uranium(VI) Extraction with CMPO-Ionic Liquid

WU Jing-Ke, SHEN Xing-Hai, CHEN Qing-De   

  1. Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory of Fundamental Science, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
  • Received:2013-03-29 Revised:2013-06-03 Published:2013-07-09
  • Contact: SHEN Xing-Hai
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (91226112, 20871009).


The electrochemical behavior of U(VI) extracted from an aqueous solution of uranyl nitrate by octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in an ionic liquid was investigated. The hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C4mimNTf2) was used in this study. Using an equimolar series method, we found that CMPO and U(VI) formed a 3:1 molar complex during the extraction process. Cyclic voltammetry was used to investigate the electrochemical behavior of the U(VI)-CMPO complex in C4mimNTf2. The U(VI)-CMPO complex was found to be quasi-reversibly reduced to a U(V)-CMPO complex. The formal redox potential (EΘ, vs Fc/Fc+) for the U(VI)/U(V) couple was determined to be (-0.885±0.008) V. Controlled-potential electrolysis of the extract gave a deposit on the surface of a platinum plate. X-ray photoelectron spectroscopy showed that the deposit contained only U(VI), U(IV), and oxygen, and the CMPO extractant and the ionic liquid were not trapped in the deposit.

Key words: ?Uranium, Ionicliquid, Extraction, Cyclicvoltammetry, Electrodeposition