Extraction and Separation of Rare Earth Metal Ions with DODGAA in Ionic liquids

Abstract

In order to apply ionic liquids (ILs) to the separation of rare earth metals, liquid-liquid extraction of a series of rare earth elements into the ILs was investigated mainly using 1-octyl-3-methylimidazolium bis(trifluoromethyl sulfonyl) imide, [C 8 mim][Tf 2 N], withN,N-dioctyldiglycol amic acid (DODGAA) as the extractant. A higher selectivity was exhibited for the heavier rare earth elements as in the n-dodecane system, and the order of the extractability of Y(III) in the IL system, situated in the heavy rare earth metals, was between Tb and Dy. This position is a little different from that for the common solvent extraction system employing organophosphorus extractants such as bis (2-ethylhexyl)phosphoric acid (D2EHPA) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC-88A). Quantitative extraction was achieved for all rare earth metals with DODGAA from sulfuric acid solutions from pH 1.5 to 4. It was confirmed that rare earth metal ions were extracted with 3 DODGAA molecules in the ILs.

Extraction of Rare-Earth Ions with an 8-Hydroxyquinoline Derivative in an Ionic Liquid

“…As for the middle rare earth, Eu, the extraction efficiency in both systems was similar. Similar behavior wherein the selectivity between light and heavy rare-earth ions was increased in the ILs compared to that in the organic solvent was observed for other extractants such as PC-88A and recently developed DODGAA (N, N-dioctyldiglycol amic acid) [8,18].…”

Highly Efficient Extraction Separation of Lanthanides Using a Diglycolamic Acid Extractant

“…The liquid-liquid extraction and liquid-membrane transfer of rare-earth metal ions from aqueous solutions containing base metal ions were performed using DODGAA, which indicated that DODGAA has higher selectivity for rare-earth metal ions than for base metal ions. [28][29][30][31] In the present study, we comprehensively investigated the extraction behavior of all Ln 3+ ions, except Pm 3+ , with DODGAA, and investigated the extraction mechanism using slope analysis, loading tests, and electrospray ionization mass spectrometry (ESI-MS) measurements. The mutual separation of individual Ln 3+ ions using DODGAA was compared with mutual separation using D2EHPA (Fig.…”

Comprehensive Extraction Study Using N,N-Dioctyldiglycolamic Acid

“…DODGAA is expected to be useful for the separation of rare-earth metal ions from foreign metal ions 9,10 as well as the mutual separation of individual rare-earth metal ions from each other. 7,8,12,23 The extractability of Sc(III) gradually increased compared with that of the other rare-earth metal ions. In fact, the slopes of the logarithmic distribution ratio versus the pH were approximately 3 for all rare-earth metal ions, except for Sc(III), and the slope for Sc(III) was 1.08, which is not equivalent to the valence of Sc(III).…”