Metal–organic framework with optimally selective xenon adsorption and separation

TLDR

Nuclear energy requires reprocessing of spent fuel, but volatile radionuclides such as xenon and krypton are released into off‑gases, and current removal relies on costly cryogenic distillation, whereas metal–organic frameworks can selectively adsorb these gases at ambient conditions. This study aims to identify the most xenon‑selective metal–organic framework through high‑throughput computational screening. The authors screened large MOF databases computationally to pinpoint SBMOF‑1 as the top candidate. SBMOF‑1 demonstrates the highest reported xenon adsorption capacity and exceptional Xe/Kr selectivity under reprocessing‑relevant conditions.

Abstract

Abstract Nuclear energy is among the most viable alternatives to our current fossil fuel-based energy economy. The mass deployment of nuclear energy as a low-emissions source requires the reprocessing of used nuclear fuel to recover fissile materials and mitigate radioactive waste. A major concern with reprocessing used nuclear fuel is the release of volatile radionuclides such as xenon and krypton that evolve into reprocessing facility off-gas in parts per million concentrations. The existing technology to remove these radioactive noble gases is a costly cryogenic distillation; alternatively, porous materials such as metal–organic frameworks have demonstrated the ability to selectively adsorb xenon and krypton at ambient conditions. Here we carry out a high-throughput computational screening of large databases of metal–organic frameworks and identify SBMOF-1 as the most selective for xenon. We affirm this prediction and report that SBMOF-1 exhibits by far the highest reported xenon adsorption capacity and a remarkable Xe/Kr selectivity under conditions pertinent to nuclear fuel reprocessing.