TEMPERATURE EFFECT ON TECHNETIUM(VII) EXTRACTION BY CMPO AND TBP

Temperature effect on the extraction of technetium(VII) was investigat ed under the conditions of the absence and presence of uranium(VI) fro m nitric acid solution by tyl(phenyl)-N,N-diisobutylcarbamoylmethylpho sphine oxide (CMPO), tributyl phosphate (TBP) and a mixture of CMPO an d TBP. The distribution coefficients of technetium by CMPO, TBP, and C MPO + TBP in the absence of uranium decreased with the increase of tem perature. In the presence of uranium, the distribution coefficients of technetium were found to be quite larger than those in the technetium alone extraction system. Their thermodynamic parameters were obtained using the temperature effects on the distribution coefficients of tec hnetium under various conditions. The information obtained from the th ermodynamic parameters was discussed taking the extraction mechanism o f technetium into account. (C) 1997 Elsevier Science B.V.