Selective Th(iv) capture from a new metal-organic framework with O groups.

Herein we report a new 4-fold interpenetrated metal-organic framework (MOF) functionalized with O groups for selective Th(iv) capture, the activated samples 1a exhibited a high adsorption capacity for pure Th(iv) ions (K = 3.16 × 10 mL g) and the amount of metal ions adsorbed on the adsorbent was 165.61 mg g. A high removal efficiency of 99.75% was achieved within 10 min with an initial Th(iv) concentration of 100 mg L and the adsorption data followed the pseudo-second-order model. In addition, the separation coefficient (S) of Th(iv) to metal ions with different valence states such as Th(iv)/La(iii), Th(iv)/Sm(iii), Th(iv)/Ho(iii), Th(iv)/Cd(ii) and Th(iv)/K(i) achieved values of 19.66, 26.83, 16.90, 11.26 and 255.79, respectively. Even given the fact that MOFs with O groups showed high affinity for Pb(ii) ions, our adsorption studies for compound 1a revealed a separation coefficient (S) of 4.36. Further, the adsorption of Th(iv) ions to compound 1a was investigated by FT-IR, SEM-EDS and XPS.