Xue Bin, Lv Yingtong, Xuan Weimin, Zhu Wenkun, Li Zijian, Zhang Linjuan, Wang Jian-Qiang
State Key Laboratory of Advanced Fiber Materials, College of Chemistry and Chemical Engineering, Donghua University, Shanghai 201620, China; Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, PR China.
Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, PR China.
J Colloid Interface Sci. 2025 Aug 15;692:137515. doi: 10.1016/j.jcis.2025.137515. Epub 2025 Apr 6.
Zirconium metal-organic cages (MOCs) have emerged as potential adsorbents for radioactive iodine absorption, one of key fission products of concern in nuclear fuel cycles. Herein a series of substituted groups functionalized Zr-MOCs were employed to investigate the influence of substituted group on iodine adsorption, in which ZrT-1-(NH) showed the highest improvement on both iodine vapor and solution-based absorption. Thereafter, five longer linkers functionalized with amino groups were chosen to construct five isoreticular MOCs for iodine absorption. Among them, ZrT-2-3,3'-(NH) and ZrT-3-2,2''-(NH) exhibited comparable iodine vapor absorption capacity compared with ZrT-1-(NH). Impressively, iodine vapor adsorption capacities (2.62 g/g and 2.50 g/g) of ZrT-1-(NH) and ZrT-3-2,2''-(NH), represent the second highest among all the MOCs. These five isoreticular MOCs displayed higher iodine uptake capacities via solution-based process than ZrT-1-(NH). The iodine/cyclohexane uptake capacities of ZrT-2-3-NH and ZrT-2-3,3'-(NH) and ZrT-3-2,2''-(NH) are the highest among all the MOCs. Raman and XPS demonstrate the strong charge transfer from the amino-substituted linkers to absorbed iodine. Synchrotron X-ray single-crystal diffraction provides the possible iodine species distribution in the cage, clarifying the host-guest interactions between the trapped iodine and MOCs. This work may motivate the rational design of MOCs with optimized structures to enhance the adsorption properties.
锆基金属有机笼状物（MOCs）已成为用于吸收放射性碘的潜在吸附剂，放射性碘是核燃料循环中关键的裂变产物之一。在此，一系列带有取代基官能团的Zr-MOCs被用于研究取代基对碘吸附的影响，其中ZrT-1-(NH)在碘蒸汽吸附和基于溶液的吸附方面都有最高的提升。此后，选择了五个用氨基官能化的更长连接体来构建五个用于碘吸附的同网状MOCs。其中，ZrT-2-3,3'-(NH)和ZrT-3-2,2''-(NH)与ZrT-1-(NH)相比，展现出相当的碘蒸汽吸附能力。令人印象深刻的是，ZrT-1-(NH)和ZrT-3-2,2''-(NH)的碘蒸汽吸附容量（分别为2.62 g/g和2.50 g/g）在所有MOCs中排名第二高。这五个同网状MOCs通过基于溶液的过程表现出比ZrT-1-(NH)更高的碘吸收能力。ZrT-2-3-NH、ZrT-2-3,3'-(NH)和ZrT-3-2,2''-(NH)的碘/环己烷吸收能力在所有MOCs中是最高的。拉曼光谱和X射线光电子能谱表明从氨基取代的连接体到吸附碘存在强烈的电荷转移。同步辐射X射线单晶衍射给出了笼状物中可能的碘物种分布，阐明了捕获的碘与MOCs之间的主客体相互作用。这项工作可能会推动对具有优化结构的MOCs进行合理设计，以增强其吸附性能。
