Thermodynamics of the extraction of selected metal ions by Di(2-ethylhexyl) alkylenediphosphonic acids.
The thermodynamics of extraction of Am(III), Sr(II) and U(VI) from aqueous HNO{sub 3} solutions by o-xylene solutions of p,p'-de(2-ethylhexyl) methylene- (H{sub 2}DEH[MDP]), ethylene-(H{sub 2}DEH[EDP]), and butylene- (H{sub 2}DEH[BuDP]) disphosphonic acids has been studied by the temperature coefficient method in the 25.0 to 60.0 C range. Both extractive aggregation and extraction stoichiometries did not change with temperature. The extraction of Am(III) by H{sub 2}DEH[MDP], and that of U(VI) by all three extractants are strongly driven by both enthalpy and entropy variations. The extraction of Sr(II) by H{sub 2}DEH[MDP] is enthalpy driven. The extraction of Am(III) by H{sub 2}DEH[EDP] and H{sub 2}DEH[BuDP] is mainly driven by entropy changes. The extraction of Sr(II) by H{sub 2}DEH[EDP] and H{sub 2}DEH[BuDP] is characterized by an unfavorable entropy change and is not indicative of a micellar-type extraction mechanism.
- Research Organization:
- Argonne National Lab., IL (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 797889
- Report Number(s):
- ANL/CHM/CP-103769
- Country of Publication:
- United States
- Language:
- English
Similar Records
Temperature effects in the extraction of metal ions by dialkyl-substituted diphosphonic acids. Part 1 : The Am(III) case.
SANS study of aggregation of the complexes formed by selected metal cations and P,P{prime}-di(2-ethylhexyl)ethane- and butane-diphosphonic acids