Imidazolate ionic liquids for high-capacity capture and reliable storage of iodine

Ruipeng Li,Yu Chen,Jianji Wang,Yanfei Zhao,Zhimin Liu,Zhiyong Li,Buxing Han

doi:10.1038/s42004-018-0067-2

Abstract

Fast, efficient capture and safe storage of radioactive iodine is of great significance in nuclear energy utilization but still remains a challenge. Here we report imidazolate ionic liquids (Im-ILs) for rapid and efficient capture, and reliable storage of iodine. These Im-ILs can chemically capture iodine to form I-substituted imidazolate ILs with an iodide counterion and the newly formed ILs can absorb iodine to form polyiodide species and low-temperature eutectic salts. For example, choline imidazolate shows iodine capture capacities of 8.7 and 17.5 g of iodine per gram of IL at 30 and 100 oC, respectively, which are, to the best of our knowledge, higher than the values (0.5–4.3 g/g) reported to date. Importantly, iodine can be stably stored in the Im-IL absorbent systems even at 100 oC. The Im-ILs have potential for application in the capture and storage of radioactive iodine.

Highlights

Fast, efficient capture and safe storage of radioactive iodine is of great significance in nuclear energy utilization but still remains a challenge
ionic liquids (ILs) have been applied in I2 capture and 1-butyl-3-methylimidazolium bromide was reported to show an I2 capture capacity of 1.9 mol I2 per molar IL15
We report a series of imidazolate ILs (Im-ILs) for fast capture and reliable storage of I2

Summary

Introduction

Efficient capture and safe storage of radioactive iodine is of great significance in nuclear energy utilization but still remains a challenge. Metal–organic frameworks[3,4,5], microporous polymer[6,7,8], charged porous aromatic frameworks[9], hydrogenbonded cross-linked organic framework[10], nonporous pillar[6] arene crystal[11], carbon-based materials[12,13], deep eutectic solvents[14], and ionic liquids (ILs)[15,16,17], have been reported for the efficient capture of I2 via physical interaction These materials usually suffer from low I2 uptake and unstable I2 storage. Ag2O@NFC aerogels[18], silver-containing mordenites[19], alkene/alkyne perovskites[20], alkali-TCNQ salts[21], and functionalized Mg-Al layered double hydroxide[22] have been reported as chemical adsorbents, whose capture efficiency are considerably dependent on their activity to react with I2, generally with shortcomings such as slow reaction rate and low capture capacity Such progress has been made in I2 capture, the absorbents/adsorbents capable of fast capturing and reliably storing I2 is still highly desirable. It is suggested that the Im-ILs reported here are highly efficient for fast capture of I2 with high capacity, and for the safe storage of this volatile compound

Methods

Results

Conclusion