Abstract
Deuterated toluene solutions of di-n-octylphosphoric acid, HDOP, containing Sr+2 extracted from 0.1 M LiNO3 aqueous solutions, were investigated by small angle neutron scattering (SANS). The extractions were also performed in the presence of either the cis-syn-cis or the cis-anti-cis stereoisomer of dicyclohexano-18-crown-6 (DCH18C6) in combination with HDOP in the toluene phase. The addition of the crown ether increased metal extraction into the organic phase over that observed with HDOP alone (synergistic extraction). The cis-syn-cis isomer was more effective than the cis-anti-cis isomer in enhancing Sr(II) extraction in the synergistic system. The SANS results confirmed that when the metal cation is extracted by HDOP present in large stoichiometric excess, the predominant species formed in the organic phase can be described as Sr(H(DOP)2)2 with 2 extra HDOP molecules solvating the complex. In the synergistic crown ether-HDOP system, the SANS data are consistent with solvent extraction data suggesting the formation of complexes containing one crown ether and two HDOP dimers. In the extraction of Sr(II) by HDOP alone, the SANS data reveal the presence of small amounts of large aggregates. Both the cis-syn-cis and cis-anti-cis isomers of DCH18C6 inhibit the formation of these aggregates. The cis-anti-cis isomer, however, despite its weaker complexation of strontium, is more effective in preventing aggregate formation.
| Original language | English |
|---|---|
| Pages (from-to) | 451-478 |
| Number of pages | 28 |
| Journal | Solvent Extraction and Ion Exchange |
| Volume | 18 |
| Issue number | 3 |
| DOIs | |
| State | Published - 2000 |
| Externally published | Yes |
Funding
This work was supported by the U.S.Department of Energy, Office of Basic Energy Science, Division ofMaterial Science (for the part performed at IPNS), and by the Environmental Management Sciences Program of the Offices of Energy Research and Environmental Management (for the part performed at the Chemistry Division of ANL) under contract number W-31-109-ENG-38. We would also like to thank D.G.Wozniak for the technical support provided at lPNS, Doris Huff of the Analytical Chemistry Division for the ICP-AES analyses, and D.R.McAIister ofLoyola University Chicago, for preparing the Sr-HOOP salt.
| Funders | Funder number |
|---|---|
| Division ofMaterial Science | |
| Office of Basic Energy Science | |
| U.S.Department of Energy | |
| Argonne National Laboratory | W-31-109-ENG-38 |