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.