Cluster‐Based Crystalline Materials for Iodine Capture

Abstract

The treatment of radioactive iodine in nuclear waste has always been a critical issue of social concern. The rational design of targeted and efficient capture materials is of great significance to the sustainable development of the ecological environment. In recent decades, crystalline materials have served as a molecular platform to study the binding process and capture mechanism of iodine molecules, enabling people to understand the interaction between radioactive iodine guests and pores intuitively. Cluster‐based crystalline materials, including molecular clusters and cluster‐based metal‐organic frameworks, are emerging candidates for iodine capture due to their aggregative binding sites, precise structural information, tunable pores/packing patterns, and abundant modifications. Herein, recent progress of different types of cluster materials and cluster‐dominated metal‐organic porous materials for iodine capture is reviewed. Research prospects, design strategies to improve the affinity for iodine and possible capture mechanisms are discussed.

Recent progress in iodine capture by macrocycles and cages

“…8 Up to now, adsorption-based solid-state materials have attracted considerable attention on radioiodine capture because of their cost effectiveness, easy operation, and the avoidance of using highly corrosive solutions. 9,10 Most studies have mainly focused on the capture of volatile I 2 , 11–13 which is also the dominant species, from liquid or gas phases using solid-state adsorbents. Several driving forces for such adsorption have been proposed, including coordinative interactions, redox reactions, Lewis acid–base interactions, charge transfer interactions, hydrogen bonding, etc.…”

“…11 Zhang et al summarized various types of cluster materials and cluster-dominated metal–organic porous materials for iodine capture. 12 In 2023, Hong et al reviewed the use of porous organic materials, including COFs and POPs, for iodine adsorption. 13 Furthermore, Han's group summarized the adsorption mechanisms employed to capture iodine and organic iodides and outlined the challenges and opportunities in this field from the perspective of materials design and system evaluation.…”

Construction of hydroxyl-functionalized hyper-crosslinked networks from polyimide for highly efficient iodine adsorption

“…Recently, functional porous absorbents such as silver-based zeolites 8 , 9 , 10 and metal-organic frameworks (MOFs) 11 , 12 , 13 have been designed for I 2 capture, but their low capture capacity, irreversible procedure and high cost have restricted their development and application. Therefore, multiple porous organic polymers (POPs) have been developed and utilized in adsorption, catalysis, and other fields to solve environmental problems.…”

Two New 1D Supramolecular Compounds Based on PbI2 for Efficient Iodine Capture

“…Through the enrichment of the food chain, radioactive iodine continues to enter the human body and participate in human metabolism, causing thyroid damage and even cancer [ 9 , 10 , 11 ]. In addition, radioactive iodine combined with volatile organic materials can cause irreversible damage to the central nervous system [ 12 ]. Moreover, many chemical and pharmaceutical enterprises are also facing the problem of iodine wastewater and waste gas treatment.…”

“…A large number of inorganic–organic hybrid crystals with novel structures have been reported, and researchers began to pay attention to the improvement of their practical application value [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Supramolecular materials combine the stability of inorganic materials and the adjustability of organic materials, which gives organic–inorganic hybrid materials unique advantages in the field of iodine molecular enrichment [ 12 ]. Some electron-rich groups, such as −NH, −NH 2 , −C=N−, heterocyclic (S, P), aromatic ring, and so on, can adsorb electron-deficient I 2 by forming charge transfer complexes, so as to improve the adsorption capacity and adsorption rate by adjusting the adsorption dynamics between organic–inorganic hybrid materials modified with electron-rich functional groups and iodine [ 28 ].…”