Shuwen Yu,Shichun Li,Huazhao Wang,Chunhua Zhu,Jingwei Hou,Sheng Cui,Xiaodong Shen,Yu Liu
The Kr/Xe separation based on membranes is of great significance for radioactive 85 Kr 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.
Shuwen Yu,Ben Qin,Fan Yang,Meiying Xie,Liyan Xue,Zhigang Zhao,Kaixian Wang
Reduced graphene oxide (rGO) membranes have shown promising separation and purification in the fields of water treatment and gas capture due to their unique physicochemical characteristics. However, how to further reduce the transport resistance of rGO membranes and improve separation performance is still a thorny issue. In this work, the reported metal-crosslinked rGO membranes showed a reverse-selective separation behaviors for the adsorbed gas molecules at low pressure. The effect of metal ions on the membrane structure and the separation performance were investigated. Metal ions not only can improve the cross-linking structure and control interlamellar spacing of rGO membranes for the precise molecular sieve, but also can provide abundant metal sites to enhance the affinity, which led to a diffusion-controlled process for the targeted gas molecules. The resulting metal-crosslinked rGO membranes presented outstanding gas permeance and selectivity for gas pairs of the He/CO 2 , N 2 /CO 2 and Kr/Xe, with the highest selectivity of 21, 11.4 and 4.1, respectively. The work will provide a new avenue towards specific molecule capture for the development of rGO membranes in the fields of natural gas purification and radioactive gas recovery.
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