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 dtluent, 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 increases from zero, K rises to a maximum (region of positive synergism): in others no positive synergism is noted. In each instance in which a maximum is found, the maximum becomes progressively more pronounced as the synergist is varied from n-decanol to TBP, tri-n-butyl phosphate, to TOPO, tri-n-octyl 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, cyclohexane and toluene diluents) is --3. Similarly, the limiting slope of the log K vs log (r-2) plot (n-decanol synergist, cyclohexane dtluent) is --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 diluert and third power in n-decanol diluert. Z-studies in the diluerts 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 H2MEHP, and possible applications of these effects are suggested. (auth)
- Research Organization:
- Argonne National Lab., Ill.
- NSA Number:
- NSA-17-008066
- OSTI ID:
- 4739276
- Journal Information:
- J. Inorg. & Nucl. Chem., Journal Name: J. Inorg. & Nucl. Chem. Vol. Vol: 24
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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