Comprehensive extraction separation study of metal ions using -dioctyldiglycolamic acid DODGAA

Shimojo, Kojiro   ; Naganawa, Hirochika  

We report on the feasibility of -dioctyldiglycolamic acid (DODGAA) as a novel extractant for selective separation of varioius metal ions in industrial solvent extraction processes. DODGAA can be synthesized simply and readily in a single step. This extractant enables the quantitative partitioning of all rare-earth metal ions (RE) from moderately acidic solutions, while showing selectivity for heavier lanthanides, and provides remarkably high extraction separation performance for RE compared with commercial extractants. In fact, the mutual separation abilities of DODGAA for light lanthanides are higher than those of organophosphorus extractants. Furthermore, we found that DODGAA is useful for the separation of RE from base metal ions. For other metal ions, DODGAA posesses great potential for the selective recovery of a noble metal ion Pd(II) from Pt(IV) and Rh(III), the removal of toxic metai ions, such as Hg(II) and Pb(II), and the recycling of In(III) from the group-13 elements.