Structural Modification of Polyacrylic Resin by Hydroxamic acid to Increase the Adsorption Performance for rare Earth ions

Abstract

Typically, traditional rare earth element (REE) extraction processes generate industrial effluents rich in REEs, resulting in significant resource waste and environmental pollution. Hence, there are important practical applications for the preparation of adsorbents with high adsorption efficiency and superior stability for the recovery of REEs. In this work, a poly(6-(N-acetyl-acryloylamino) hexyl hydroxamic acid) (PAAHA) chelating resin was successfully prepared by grafting 6-acetyl amino hexyl hydroxamic acid onto polyacrylic resin (D113). The PAAHA chelating resin was utilized for the removal of La³⁺, Ce³⁺, and Y³⁺, and the maximum uptake capacities determined from the batch adsorption experiments were 2.10, 2.38, and 3.98 mmol/g, respectively, which were 3.09, 3.05, and 9.05 times greater than those of the D113 resin. The results demonstrated that the adsorption process was consistent with the pseudo-second-order kinetic and Langmuir isotherm models, suggesting that monolayer chemisorption was the dominant process. Concurrently, five successive adsorption‒desorption cycles revealed that the PAAHA chelating resin displayed remarkable reproducibility and stability. Notably, the –CONHOH group exhibited a marked affinity for REEs, resulting in the formation of stable five-membered rings via mechanism characterization. In summary, this resin represents a novel strategy for designing adsorbents and shows considerable promise for the remediation of mining tailings containing REEs.

Graphical Abstract