High retention volume covalent organic polymer for xenon capture: Dynamic separation of Xe and Kr

Abstract

Xenon capture and Xe/Kr separation are important processes in industry. For instance, Xe/Kr separation is an indispensable step in recycle and treatment of nuclear fuel emission. Among different separation methods, selectively adsorb gas molecules using porous materials is a promising way to reduce the high energy consumption in traditional cryogenic distillation. However, many reported adsorbents still face the challenges of: i) poor separation property at low Xe/Kr concentrations; ii) insufficient retention volumes, which influence the viability of whole process. In this work, we present a stable covalent organic polymer, i.e., COP-14, showing promising potential for Xe/Kr separiton. In dynamic breakthrough experiments, COP-14 successfully separates low concentration Xe (350 ppm) and Kr (35 ppm) from target gas mixtures. Meanwhile, the xenon retention volume per gram (1700 mL g−1 at 298 K) of COP-14 in dynamics absorption process achieves 3.8 times of benchmark active carbon. The good performance of the newly devloped COP-14 mainly from its rich nitrogen sites and suitable pore size with xenon molecues. The promising results of COP-14 on Xe/Kr separation in this work provide a promising way for designing efficient Xe/Kr separation mateirals.

Keywords

• Xe/Kr separation
• Noble gas
• Gas separation
• Porous organic polymers
• Breakthrough separation