Extraction behaviors of trivalent lanthanides from nitrate medium by selected substituted malonamides

The extraction of La(III), Pr(III), Nd(III) Sm(III), Eu(III), Gd(III) Tb(III), Dy(III), and Er(III) from nitrate medium by a series of structurally related malonamides (MA) diluted with toluene has been studied. The considered malonamides were synthesized with different substituting groups including alkyl, cyclohexyl, and oxyalkyl chains. This series allowed for a systematic determination of the effect of the structure on the extraction of trivalent lanthanides. Distribution ratios of the investigated metal ions have been determined as a function of nitric acid concentration, diluent type, extractant concentration and salting-out agent as well as temperature. The stoichiometries of the extracted species of La(III), Sm(III), Tb(III), and Er(III) were conformed to be tri-solvates. The extracted species were also studied using IR spectra.