Extraction and recovery of rare earths by chelating phenolic copolymers bearing diglycolamic acid or diglycolamide moieties

Extraction and recovery of rare earth elements (REEs) have been studied using ion-exchange and chelating process thanks to phenol copolymeric resins. The ion-exchange and chelating resins have been prepared through an alkaline polycondensation reaction of phenolic diglycolamic acid or diglycolamide derivatives with admixture of phenol, catechol or resorcinol in the presence of formaldehyde as crosslinker. The phenol copolymeric resins were fully characterized and involved in sorption experiments. The sorption experiments of rare earth elements have been investigated in different acidic conditions. Lanthanum (La), europium (Eu) and ytterbium (Yb) were chosen to represent the light, medium and heavy REEs respectively. Changes in the extraction properties of the copolymeric resins have been observed depending on the nature of chelating groups in the phenolic matrices and the extraction conditions. The obtained results indicate that the synthesized material exhibit good sorbent properties for REEs with cation uptake capacity in the range 50-100 mg/g and in some cases above 150 mg/g.