Crosslinked microporous polyarylate membranes with high Kr/Xe separation performance and high stability under irradiation

The Kr/Xe separation based on membranes is of great significance for radioactive ⁸⁵Kr capture from nuclear fuel reprocessing plants and expensive Xe production, thus the membrane material that has both high separation performance and stability is highly sought after. Herein, the crosslinked polymeric micro-porous polyarylate (PAR) membrane was synthesized by interfacial polymerization, and its Kr/Xe separation performance and stability under various conditions including γ irradiation were investigated. The PAR membrane displays Kr permeance of 0.22 GPU and Kr/Xe selectivity of 3.6 tested with mixed gas at room temperature, which is better than other reported polymeric membranes and even better than the amorphous carbon membrane. After the γ irradiation, the PAR can preserve its chemical structures, while the physical ageing is accelerated, which leads to only 25% decrease in Kr/Xe selectivity after 20 kGy irradiation. This work demonstrates that the micro-porosity and the crosslinking structures play crucial roles in improving both separation performance and stability of polymeric membranes for radioactive Kr/Xe separation.