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.