Iodine nanotrap for highly efficient iodine capture under high temperature

Abstract

Covalent organic frameworks have been recognized as promising porous materials for the radioactive iodine capture. However, most COFs often suffer from low adsorption capacity under practical conditions (typically ≥ 150 °C, ≤ 150 ppmv I2) due to the lack of strong binding sites and low affinity toward iodine, which restricts their application in industrial relevant conditions. Here, we develop a strategy of constructing highly efficient I2 nanotraps by manipulating two kinds of adsorption sites (ionic binding sites and Lewis binding sites) located at adjacent spatial positions, thereby realizing the synergistic binding toward I2. The obtained I2 nanotrap 4F-iCOF-TpBpy-I- delivers a remarkable I2 uptake capacity of 37 wt% at 150 °C and 150 ppmv of I2, which illustrate a record-high value for all COFs reported so far. This work opens a new avenue for the rational design of COF materials toward highly efficient I2 capture and related application.