Solvent extraction of uranium(VI), plutonium(VI) and americium(III) with HTTA/HPMBP using mono- and bi-functional neutral donors: Synergism and thermodynamics

• Published in: Journal of radioanalytical and nuclear chemistry Vol. 245; no. 3; pp. 623 - 628
• Main Authors: Aggarwal, S K, Pai, S A, Lohithakshan, K V, Mithapara, P D
• Format: Journal Article
• Language: English
• Published: 01-09-2000
• ISSN: 0236-5731
• DOI: 10.1023/A:1006794201866

Synergistic extraction of hexavalent uranium and plutonium as well as trivalent americium was studied in HNO sub 3 with thenoyl, trifluoro-acetone (HTTA)/1-phenyl, 3-methyl, 4-benzoyl pyrazolone-5 (HPMBP) in combination with neutral donors viz. DPSO, TBP, TOPO (mono-functional) and DBDECMP, DHDECMP, CMPO (bi-functional) with wide basicity range using benzene as diluent. A linear correlation was observed when the equilibrium constant log K sub s for the organic phase synergistic reaction of both U(VI) and Pu(VI) with either of the chelating agents HTTA or HPMBP was plotted vs. the basicity (log K sub h ) of the donor (both mono- and bi-functional) indicating bi-functional donors also behave as monofunctional. This was supported by the thermodynamic data ( Delta G deg , Delta H deg , Delta S deg ) obtained for these systems. The organic phase adduct formation reactions were identified for the above systems from the thermodynamic data. In the Am(III) HTTA system log K sub s values of bi-functional donors were found to be very high and deviate from the linear plot (log K sub s vs. log K sub s ) obtained for mono-functional donors, indicating that they function as bi-functional for the Am(III) /HTTA system studied. This was supported by high +ve Delta S deg values obtained for this system.