Speciation of lanthanide ions in the organic phase after extraction from nitrate media by basic extractants

A speciation study was carried out for lanthanide complexes formed in the organic phase after solvent extraction with quaternary ammonium and phosphonium nitrate extractants. These extractants are liquid at room temperature and were applied in their undiluted form. A comparison was made between the...

Full description

Saved in:
Bibliographic Details
Published in:RSC advances 2018-01, Vol.8 (56), p.3244-3254
Main Authors: Onghena, Bieke, Papagni, Eleonora, Souza, Ernesto Rezende, Banerjee, Dipanjan, Binnemans, Koen, Vander Hoogerstraete, Tom
Format: Article
Language:English
Subjects:
Aliquat
Chemistry
Coordination compounds
Fourier transforms
Luminescence
Nitrates
NMR
Nuclear magnetic resonance
Promethium
Solvent extraction
Solvents
Speciation
Spectrum analysis
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A speciation study was carried out for lanthanide complexes formed in the organic phase after solvent extraction with quaternary ammonium and phosphonium nitrate extractants. These extractants are liquid at room temperature and were applied in their undiluted form. A comparison was made between the quaternary compound trihexyl(tetradecyl)phosphonium nitrate, the nitrate form of the commercial extractant Cyphos IL 101, and Aliquat 336 nitrate, the nitrate form of the commercial trialkylmethylammonium chloride extractant Aliquat 336 (alkyl = mixture of C8 and C10 chains). The structures of the lanthanide complexes across the entire lanthanide series (with the exception of promethium) were determined by a combination of solvent extraction techniques, FTIR, NMR, high-resolution steady-state luminescence spectroscopy, luminescence life time measurements, elemental analysis and EXAFS spectroscopy. The results suggest that the lanthanide ions form an anionic nitrate complex in the organic phase by coordinating with five bidentate nitrate ligands. Charge neutralization is provided by two counter cations of the extractant present in the outer coordination sphere of the complex. Furthermore, it is suggested that the pentanitrato complex is the sole lanthanide species that is formed in significant concentrations in the organic phase. Lanthanides are extracted to basic nitrate-based extractants, like trihexyl(tetradecyl)phosphonium nitrate, as pentanitrato lanthanide complexes.
ISSN:2046-2069
2046-2069
DOI:10.1039/c8ra06712k