Meso/macropore emerging from MOF granulation for enhancing performance in the Xe/Kr separation

The eco-friendly water/PVA system (PVA = polyvinyl alcohol) was employed to granulate SBMOF-1 powder to form SBMOF-1@20%PVA beads. The granulated beads maintained the high crystallinity of SBMOF-1 with the emergence of meso/macropores at 3.8, 50, and 76 nm. Owing to its benefit for mass diffusion, the presence of meso/macro porosity led to ∼128% enhancement of the Xe uptake capacity (based on SBMOF-1) of SBMOF-1@20%PVA beads over SBMOF-1 powder at 20% Xe broke through. This further enabled Xe/Kr separation from the simulated used nuclear fuel (UNF) reprocessing off-gas. Moreover, an easier and faster regeneration of SBMOF-1@20%PVA over SBMOF-1 powder through helium purge was obtained at room temperature. These findings demonstrate an enhanced working efficiency of the granulated SBMOF-1 beads over the powder samples by improving uptake capacity, saving energy for regeneration at high temperatures and cooling time after the heating-up regeneration, thereby highlighting the benefit of our engineering protocol in enhancing separation performance via MOF granulation.