A Chitosan-Based Y3+-Imprinted Hydrogel with Reversible Thermo-Responsibility for the Recovery of Rare Earth Metal

Recovery of rare earth metal is a global concern for resource-efficient application and high-tech industry development. In this study, a new Y3+ adsorbent, namely chitosan-based Y3+-imprinted hydrogel with reversible thermo-responsibility (CYIT) was synthesized, using Y3+ as the template ion. The obtained CYIT was compre-hensively characterized by means of DSC, FTIR, LRS, TGA, SEM, and XPS. As revealed from the results, CYIT possesses stable reversible thermo-responsibility confirmed by the phase transition temperature ranging from 29.2 degrees C to 38.4 degrees C. Its maximum adsorption capacity on Y3+ is up to 160.0 mg/g, much higher than the cor-responding performance of similar hydrogels. More significantly, this type of adsorbent could be effectively regenerated by simply leaching with cold water and the desorption efficiency reached 96.2 % after wash by cold water at 15 degrees C for 25 min. Besides, the remarkable reusability should also be highlighted, for the adsorption capacity and desorption efficiency remained as 124.8 mg/g and 90.0 %, respectively, after five adsorp-tion-desorption cycles. In the coexistence of other interfering metal ions (including La3+, Gd3+, Cu2+, Al3+, and Fe3+), CYIT also exhibited better adsorption selectivity than the corresponding adsorbent without Y3+ -imprinting.