Amine-functionalized Cr-MIL-101 as sorbents for selective recovery of rare earth elements.

초록

Metal?organic frameworks (MOFs), a class of organic-inorganic hybrid materials composed of metal clusters interconnected through a rigid organic linker, are emerging as important functional materials due to their high surface area, porosity and diverse functionalization available. Recently, it was reported that MOFs with amine functional groups could be used as solid-phase sorbents for actinide extraction. In this work, we prepared the acid-resistant chromium-based MOF, Cr- MIL-101, and its amino derivatives; MIL101-NH2, MIL101-ED (ED; Ethanediamine), and MIL-101-DETA (DETA; Diethylenetramine) by the post-synthesis methods and explored their potential usage in separation and recovery of rare earth metals (REEs); Sm3+, Gd3+, and La3+ from aqueous solutions. The prepared materials were characterized by XRD, BET, FT-IR, EA, and XPS analyses to confirm the successful modification of amino groups. The sorption of REEs onto the prepared materials as a function of solution pH, contact time, initial concentration of REEs were studied in detail. The chemical stability and loss of efficiency of these were also investigated to evaluate their potential as high-performance, reusable sorbents for REEs.