Organization of diglycolamides on resorcinarene cavitand and its effect on the selective extraction and separation of HREEs

Two calix(4)resorcinarene based cavitands, one that contains four triazole units, calix(4)resorcinarene-tetra(hexyltriazole) CR4-Tz LI, and another that contains four triazole diglycolamide units, calix(4)resorcinarene-tetra(didecyldiglycolamidetriazole) CR4-Tz-DDDGA LII, were synthesized and fully characterized by IR, NMR, and MS. The efficiency of the two cavitands were compared toward the extraction of 7 lanthanides (Ce(III), Nd(III), Sm(III), Gd(III), Dy(III), Er(III), Yb(III)) in chloroform from 5 M HNO3. The extraction study showed that LI, which contains only the triazole units, is unable to extract any of the targeted metals. The effects of the organization and diluents on the distribution coefficients and the selectivity of LII were also studied toward the same lanthanide series at the same acidity. The obtained results showed that the cavitand is selective toward heavy lanthanides irrespective of the diluents. The extraction and stripping experiments of the 7 Ln(III) and the separation of Nd and Dy from a Fe-B-Nd-Dy leaching solution were performed.