Poly(vinyl diglycolic acid ester)-Grafted Polyethylene/Polypropylene Fiber Adsorbent for Selective Recovery of Samarium

Poly(vinyl diglycolic acid ester)-grafted polyethylene fabric (PE-PDGA) containing 1.71-4.58 mmol/g millimolar equivalents (meqs) of immobilized tridentate ligand were prepared through radiation-induced graft polymerization of vinyl acetate, saponification, and a ring-opening reaction of diglycolic anhydride. PE-PDGA can adsorb rare earth metal ions, such as Sm, Nd, and Dy, at pH 2.5, with an increase in the removal ratio of the Sm, Nd, and Dy ions observed with an increase in the pH from 2.5 to 4. Furthermore, PE-PDGA more selectively adsorbs rare earth metals, such as Sm, Nd, and Dy, than other metals, such as Cu, Zn, and Co, in the pH range of 2.5-4; 73 mg Sm was adsorbed on 1 g PE-PDGA at an initial metal concentration of 100 ppm at pH 3, while Co was not adsorbed on PE-PDGA in the initial metal concentration range of 10 to 100 ppm. Thus, PE-PDGA showed high selectivity toward rare earth metals, and Sm and Co could be separated effectively.