Investigation of xenon adsorption in three types of porous materials

Abstract

The recovery of xenon from atmospheric air, based on highly efficient and selective adsorption, could replace the current cost-intensive cryogenic distillation generally used for xenon production. In addition, adsorption improvements for the measurement of ultra-low levels of radioactive xenon in the atmosphere could increase the capability of the verification system for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). In the same context, enhanced radioactive xenon trapping systems at civilian nuclear installations could also improve the verification capability, as this would further reduce the atmospheric radioactive xenon background. Activated carbon has been used for more than 60 years in the nuclear industry to recover radioactive xenon from gaseous effluents. About 20 years ago, researchers have demonstrated that some silver-exchanged zeolites had a higher Xe adsorption capacity at low Xe-partial pressures. The lack of knowledge on the durability of these zeolites did not yet allow their use with highly radioactive gas streams. More recently, some metal-organic frameworks have been demonstrated to be quite selective for xenon over other gas components, which could open a new opportunity in these fields. Ideally, adsorbents that are capable of trapping large amounts of xenon whilst being highly selective for xenon are looked for. In addition, these adsorbents should be durable against multiple temperature swing adsorption cycles as well as against severe irradiation. In this poster, the measurement of xenon breakthrough curves over a range of conditions, used for the investigation of the Xe adsorption properties, will be presented and the results obtained on the three types of adsorbents will be discussed. Other characterization techniques (e.g. liquid nitrogen adsorption and thermal gravimetric analysis) used to support such research, through the identification of promising materials and to investigate their durability, will be addressed.