SANS study of aggregation of the complexes formed by selected metal cations and P,P{prime}-di(2-ethylhexyl)ethane- and butane-diphosphonic acids
The aggregation of several metal complexes formed during solvent extraction with P,P{prime}-di(2-ethylhexyl) ethanediphosphonic acid, H{sub 2}DEH[EDO], and by P,P{prime}-di(2-ethylhexyl) butanediphosphonic acid, H{sub 2}DEH[BuDP], in deuterated toluene, has been investigated by small angle neutron scattering (SANS). With H{sub 2}DEH[EDP], the extraction of Ca(II), La(III) and U(VI) does not disrupt the cyclic hexameric structure of the ligand in solution. Fe(III) and Th(IV) complexes of H{sub 2}DEH[EDP], on the other hand, exhibit a very modest tendency to aggregate but only at very high metal loading in the organic phase. With H{sub 2}DEH[BuDP], the extraction of Ca(II), La(III), U(VI) and Th(IV) is not accompanied by significant aggregation of the metal complexes. The Fe(III)-H{sub 2}DEH[BuDP] complexes, however, form long cylindrical aggregates similar to those previously observed with P,P{prime}-di(2-ethylhexyl) methanediphosphonic acid, H{sub 2}DEH[mdp]. The aggregation behavior of the various metal-extractant species is discussed in light of the information obtained from earlier solvent extraction, vapor pressure osmometry, and infrared spectroscopy studies.
- Research Organization:
- Argonne National Lab., IL (US)
- Sponsoring Organization:
- US Department of Energy
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 20000554
- Journal Information:
- Solvent Extraction and Ion Exchange, Journal Name: Solvent Extraction and Ion Exchange Journal Issue: 5 Vol. 17; ISSN 0736-6299; ISSN SEIEDB
- Country of Publication:
- United States
- Language:
- English
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