Extraction separation of Am(III) and Eu(III) using divalent quadridentate Schiff bases-bis-salicylaldehyde ethylenediamine

Abstract

For the selective extraction of Am(III) and Eu(III), quadridentate divalent phenolic Schiff bases-bis- salicylaldehyde ethylenediamine (H2salen) was investi- gated as a kind of extractant. The influences of alkaline cation, inorganic anion, ionic strength, pH and the con- centration of H2salen on the distribution ratio of Am(III) and Eu(III) were investigated in detail. As a result, Am(III) and Eu(III) made anionic 1:1 complexes with the ligand (H2salen) and could be extracted into nitrobenzene as ion- pairs with a suitable monovalent counter anion in the aqueous solution, the extracted species were possibly of the type Am(H2salen) Eu(salen)Cl and Eu(H2salen)Cl3, respectively. The extractability of Eu(III) was significantly stronger than that of Am(III) and the maximum separation factor, SF(Am/Eu), was 96 at pH 4.0. The results indicated that H2salen had good selectivity for Am(III) and Eu(III).