Flexible interdigitated layered framework with multiple accessible active sites for high-performance CH3I capture

The development of adsorbent materials for effective capture of radioactive iodomethane (CH 3 I) from the off-gas of used nuclear fuel reprocessing, remains a significant and challenging line of research because currently state-of-art adsorbents still suffer from low binding affinity with CH 3 I. Here, we proposed a brand-new adsorption topological structure by developing a 2D interdigitated layered framework, named SCU-20, featuring slide-like channel with multiple active sites for CH 3 I capture. The responsive rotating-adaptive aperture of SCU-20 enables the optimal utilization of all active sites within the pore for highly selective recognition and capture of CH 3 I. A record-breaking CH 3 I uptake capacity of 1.84 g/g was achieved under static sorption conditions with saturated CH 3 I vapor. Both experimental and theoretical findings demonstrated that the exceptional uptake of SCU-20 towards CH 3 I can be attributed to the confined physical electrostatic adsorption of F sites, coupled with the chemical nitrogen methylation reaction with uncoordinated N atoms of pyrazine. Moreover, dynamic CH 3 I uptake capacity potentially allows for the capture of CH 3 I in simulated real-world off gas reprocessing conditions. This study highlights the potential of SCU-20 as a promising candidate for efficient capture of iodine species and contributes to the development of effective solutions for radioactive iodine remediation.