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Interpretation of third phase formation in the Th(IV)-HNO{sub3}, TBP-n-octane system with baxter's sticky spheres model.

Journal Article · · Solvent Extr. Ion Exch.
Small-angle neutron scattering (SANS) data for the tri-n-butylphosphate (TBP)-n-octane, HNO{sub 3}-Th(NO{sub 3}){sub 4} solvent extraction system, obtained under a variety of experimental conditions, have been interpreted using two different models. The particle growth model led to unrealistic results. The Baxter model for hard-spheres with surface adhesion, on the other hand, was more successful. According to this model, the increase in scattering intensity in the low Q range observed when increasing amounts of Th(NO{sub 3}){sub 4} are extracted into the organic phase, has been interpreted as arising from interactions between small reverse micelles containing three TBP molecules. Upon extraction of Th(NO{sub 3}){sub 4}, the micelles interact through attractive forces between their polar cores with a potential energy of up to about 2 k{sub B}T. The intermicellar attraction, under suitable conditions, leads to third phase formation. Upon phase splitting, most of the solutes of the original organic phase separate in a continuous phase containing interspersed layers of n-octane.
Research Organization:
Argonne National Laboratory (ANL)
Sponsoring Organization:
SC
DOE Contract Number:
AC02-06CH11357
OSTI ID:
961439
Report Number(s):
ANL/CHM/JA-47839
Journal Information:
Solvent Extr. Ion Exch., Journal Name: Solvent Extr. Ion Exch. Journal Issue: 3 ; 2004 Vol. 22; ISSN 0736-6299; ISSN SEIEDB
Country of Publication:
United States
Language:
ENGLISH