SYNERGISTIC EFFECTS IN THE EXTRACTION OF SELECTED METALLIC CATIONS BY MONO (2-ETHYL HEXYL) PHOSPHORIC ACID
The effect of synergistic agents upon the extraction of M(III) lanthanides, Y(III), Am(III), Cm(III), Th(IV), and U(VI) by H/sub 2/MEHP, mono 2- ethyl hexyl phosphoric acid, in a carrier diluent from aqueous HCl was investigated as a function of carrier diluent, synergistic agent, concentration of H/sub 2/MEHP and Z of M(III) lanthanides. It was found that a plot of log K vs log (r-0.5) or log (r-2), depending upon the synergist, is more meaningful than a plot of log K vs F or log F of the synergist, where r is the ratio, (F of synergist/F of H/sub 2/MEHP). For some elements as r increased from zero, K rose to a maximum (region of positive synergism); in others no positive synergism was noted. In each instance in which a maximum was found, the maximum became progressively more pronounced as the synergist was varied from ndecanol to TBP (tri-n-butyl phosphate) to TOPO (tri-noctyl phosphine oxide). In the negative synergism range, the limiting slope of the log K vs log (r-0.5) plot for all of the M(III) examples studied (TBP synergist and cyclohexane and toluene diluents) was --3. Similarly, the limiting slope of the log K vs log (r-2) plot (n-decanol synergist and cyclohexane diluent) was -3 for M(III), -4 for Th(IV), and -2 for U(VI). The extractant dependency for Eu(III) and Am(III) by H/sub 2/MEHP in the absence of synergist is shown to be first power in toluene diluent and third power in n-decanol diluent. Z-studies in the diluents toluene, cyclohexane, and n-decanol are included. Tentative explanations of the negative synergistic effects are Proposed in terms of assumed chemical interaction betWeen synergist and H/sub 2/MEHP; and possible applications of these effects are suggested. (auth)
- Research Organization:
- Argonne National Lab., Ill.
- DOE Contract Number:
- W-31109-ENG-38
- NSA Number:
- NSA-17-006188
- OSTI ID:
- 4736731
- Report Number(s):
- TID-15271; UAC-5922
- Country of Publication:
- United States
- Language:
- English
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