Preparation of Polymeric Adsorbents Bearing Diglycolamic Acid Ligands for Rare Earth Elements

We synthesized polymeric adsorbents modified with diglycolamic acid ligands for the recovery of rare earth elements. Styrene, divinylbenzene, and glycidyl methacrylate were copolymerized by suspension polymerization in the presence of diluent mixtures of heptane and toluene. Varying the composition of the diluent mixtures changed the pore characteristics of the polymeric particles; the highest specific surface area (51.2 m²/g) was obtained with mixtures of equal volumes of heptane and toluene. Polymeric adsorbents were prepared by functionalizing the synthesized polymeric particles with amino groups and then diglycolamic acid ligands. The content of the amino groups was almost constant, whereas that of the diglycolamic acid ligands depended on the specific surface area of the adsorbents. The synthesized polymeric adsorbents selectively adsorbed rare earth elements from a solution containing rare earth and base metal ions. The high adsorption rate of the adsorbents was due to their large specific surface area.