Water-Stable Metal–Organic Framework Material with Uncoordinated Terpyridine Site for Selective Th(IV)/Ln(III) Separation

Here in this article, [Ln­(μ2-OH)­(dtp)­(H2O)]­[Ln = Ho­(III) and Tb­(III)] is prepared using a solvothermal method to assemble the rare earth (RE) ion and the H2dtp ligand (H2dtp = 4′-(3, 5-dicarboxyphenyl)-4,2′:6′4″-terpyridine). The obtained metal–organic framework (MOF) materials were characterized with X-ray diffraction (XRD), infred spectrum (IR), thermogravimetric analysis (TGA). The prepared two MOF exhibits 2D layer structures, respectively. To our knowledge, the Ln-MOF material with uncoordinated terpyridine site has never been developed for Thorium (Th) separation. Therefore, we attempted to use these MOF materials for the purpose of separating Th­(IV) from REs in the aqueous phase. The separation factors of Th/Y, Th/La, Th/Ce, Th/Eu, Th/Lu reach 21, 19.2, 18.9, 7.5, 6.2, respectively. Moreover, the MOF materials could remain stable until 500 °C, which exhibit good selectivities and stabilities for the Th­(IV)/REs­(III) separation.