Reverse-micelle formation in the partitioning of trivalent F-element cations by biphasic systems containing a tetraalkyldiglycolamide
The conditions for reverse-micelle formation were studied for solutions of tetra-n-octyldiglycolamide (TODGA) in alkane diluents equilibrated with aqueous solutions of nitric or hydrochloric acids in the presence and absence of Nd3+. Small-angle neutron scattering, vapor-pressure osmometry, and tens...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1992. - 23(2007), 9 vom: 24. Apr., Seite 4765-74 |
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| Weitere Verfasser: | , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2007
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article Cations Glycolates Micelles Solutions tetra-n-octyldiglycolamide Water 059QF0KO0R Neodymium 2I87U3734A mehr... |
| Zusammenfassung: | The conditions for reverse-micelle formation were studied for solutions of tetra-n-octyldiglycolamide (TODGA) in alkane diluents equilibrated with aqueous solutions of nitric or hydrochloric acids in the presence and absence of Nd3+. Small-angle neutron scattering, vapor-pressure osmometry, and tensiometry are all consistent with the partial formation of TODGA dimers at the lowest acidities, transitioning to a polydisperse mixture containing TODGA monomers, dimers, and small reverse-micelles of TODGA tetramers at aqueous nitric acid acidities of 0.7 M or higher in the absence of Nd. Application of the Baxter model to the samples containing 0.005-0.015 M Nd reveals the persistence of tetrameric TODGA reverse-micelles with significant interparticle attraction between the polar cores of the micelles that increases with increasing organic phase concentrations of acid or Nd. Our experimental findings suggest that the peculiar behavior of TODGA with respect to the extraction of trivalent lanthanide and actinide cations arises from the affinity of these metal cations for the preformed TODGA reverse-micelle tetramers |
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| Beschreibung: | Date Completed 12.06.2007 Date Revised 21.11.2013 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1520-5827 |