A Double-Walled Thorium-Based Metal-Organic Framework as a Promising Dual-Function Absorbent for Efficiently Capturing Iodine and Dyes

摘要

We prepared a rare thorium metal-organic framework (MOF) (Th-TATAB) with a double-walled tetrahedral cage structure and giant unit cell volume of 43 513 angstrom(3), which is the largest of all reported thorium-based MOFs to our knowledge. The unique structural character allows the thorium-based MOF to exhibit exceptional adsorption properties toward I-2 and dyes with different charges. The experimental results show that in cyclohexane solution the absorption ability of Th-TATAB toward I-2 can reach about 750 mg/g, and especially the removal efficiency in cyclohexane solution (0.01 mol/L) can reach 90% in 3 h, which far exceeded that of reported [Zn-2(tptc)-(apy)(2-x)(H2O)(x)]center dot H2O (80%, 48 h) and MIL-101-NH2 (90%, 30 h). Furthermore, the simultaneous removal of molecules with different charges is very challenging, while Th-TATAB displays excellent adsorption properties for anionic, neutral, and cationic dyes individually and simultaneously from aqueous solution. The exploration of the adsorption performance of MOF Th-TATAB for iodine in cyclohexane solution and dye contaminants in aqueous solution is of great significance for environmental aspects, which provides a new strategy for opening up the potential applications of thorium-based MOFs and understanding actinides chemistry.