Thermal-Responsive Conjugated Micropore Polymers for Smart Capture of Volatile Iodine.
Meiyun XuQingling HeFulong ChenZhe ZhaoZiyu WangDaoben HuaPublished in: ACS applied materials & interfaces (2023)
The capture of radioiodine is crucial for nuclear security and environmental protection due to its volatility and superior environmental fluidity. Herein, we propose a strategy of "temperature-dependent gate" based on a swellable conjugated microporous polymer (SCMP) to significantly improve the capture of volatile iodine. The SCMP is constructed via the Buchwald-Hartwig coupling reaction of building monomers containing amines. It possesses a hierarchical pore structure with restricted pores, which can be "opened" and "closed" by changing the temperature. By virtue of the thermal-responsive pore structure, it reaches adsorption equilibrium for iodine in 2 h with a capacity of 4.3 g g -1 at 90 °C and retains 92.8% adsorbed iodine at room temperature. The SCMP also exhibits a high adsorption capacity up to 3.5 g g -1 for dissolved iodine within 10 min, as well as good radiation resistance and high selectivity for iodine against moisture, VOCs, and HNO 3 vapor. The mechanism is clarified for effective iodine capture and caging based on the relationship between temperature and the pore structure. This work develops not only a strategy to enhance the capture of gaseous and dissolved iodine but also a new adsorption mechanism for iodine capture, which can be extended to the separation and caging of resources or volatile pollutants in other fields.