Thermal-Responsive Conjugated Micropore Polymers for Smart Capture of Volatile Iodine

The capture of radioiodine is crucial for nuclear securityandenvironmental protection due to its volatility and superior environmentalfluidity. Herein, we propose a strategy of "temperature-dependentgate" based on a swellable conjugated microporous polymer (SCMP)to significantly improve the capture of volatile iodine. The SCMPis constructed via the Buchwald-Hartwig couplingreaction of building monomers containing amines. It possesses a hierarchicalpore structure with restricted pores, which can be "opened"and "closed" by changing the temperature. By virtueof the thermal-responsive pore structure, it reaches adsorption equilibriumfor iodine in 2 h with a capacity of 4.3 g g(-1) at90 & DEG;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 goodradiation resistance and high selectivity for iodine against moisture,VOCs, and HNO3 vapor. The mechanism is clarified for effectiveiodine capture and caging based on the relationship between temperatureand the pore structure. This work develops not only a strategy toenhance the capture of gaseous and dissolved iodine but also a newadsorption mechanism for iodine capture, which can be extended tothe separation and caging of resources or volatile pollutants in otherfields.