Crystalline Metallo-Organic Cage by Triphenylene-Cored Hexaterpyridine for Fast Iodine Capture

In recent years, radioactive iodine capture has playedan importantrole in nuclear waste treatment. However, most of the adsorbents possesslow economic efficiency and undesirable reutilization in practicalapplication. In this work, a terpyridine-based porous metallo-organiccage was assembled for iodine adsorption. Through synchrotron X-rayanalysis, the metallo-cage was found to have a porous hierarchicalpacking mode with inherent cavity and packing channel. By taking advantageof polycyclic aromatic units and charged ⟨tpy-Zn2+-tpy⟩ (tpy = terpyridine) coordination sites in the structure,this nanocage exhibits an excellent ability to capture iodine in boththe gas phase and aqueous medium, and the crystal state of the nanocageshows an ultrafast kinetic process of capturing I-2 in aqueoussolution within 5 min. The calculated maximum sorption capacitiesfor I-2 based on the Langmuir isotherm models are 1731 and1487 mg g(-1) for amorphous and crystalline nanocages,which is noticeably higher than most of the reported iodine sorbentmaterials in the aqueous phase. This work not only provides a rareexample of iodine adsorption by a terpyridyl-based porous cage butalso expands the applications of terpyridine coordination systemsinto iodine capture.

Automated summary

In recent years, a terpyridine-based porous metallo-organic cage has been developed for efficient radioactive iodine capture. The cage exhibits excellent adsorption ability in both the gas phase and aqueous medium, with ultrafast kinetics for capturing I-2 in aqueous solution. The maximum sorption capacities for I-2 are significantly higher than most reported iodine sorbent materials in the aqueous phase.