Capture and Removal of Iodine by a Fluorinated Leaning Pillar[6]arene with Host–Guest Interactions

Abstract

Volatile radioactive pollutants are posing great challenges to global environment. Volatile radioactive iodine, which is one of the primary environmental pollutants from nuclear power plants, spreads rapidly in water and air and increases risk to human health. Therefore, the research for appropriate adsorbents to capture iodine with long-term storage is crucial. In this study, we report that easily obtained fluorinated leaning pillar[6]arene FP6 is a new adsorbent for iodine capture with robust moisture and thermal stability. Crystalline solid FP6 solid can capture not only volatile iodine in the air but also iodine dissolved in aqueous solutions with fast adsorption speed and high up-take capacity. Host–guest interactions between FP6 and iodine indicates that iodine molecule is threaded into the cavity of the cyclic host FP6 to form a host-guest complex driven by C−F ⋅⋅⋅ I halogen bonding interactions. Moreover, the regeneration of FP6 is simple and efficient, and it can be regenerated at least five times by simply heating under vacuum at 120 °C for 3 hours without losing iodine capture capacity. The excellent iodine pollutant removal ability demonstrates the promise of FP6 for pollutant treatment.