Ion-Exchanged SAPO-34 Membranes for Krypton-Xenon Separation: Control of Permeation Properties and Fabrication of Hollow Fiber Membranes
Ion-Exchanged SAPO-34 Membranes for Krypton-Xenon Separation: Control of Permeation Properties and Fabrication of Hollow Fiber Membranes
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DOI：
10.1021/acsami.7b18244
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发表时间：
2018-02-21
影响因子：
9.5
通讯作者：
Nair, Sankar
中科院分区：
文献类型：
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作者：
Kwon, Yeon Hye;Min, Byunghyun;Nair, Sankar
在废核燃料后处理中，从Kr-136中分离放射性同位素Kr-85具有重要意义。基于沸石分子筛如菱沸石SAPO-34的膜分离是能量密集型低温蒸馏的有吸引力的替代方案。我们报告的SAPO-34膜的合成具有相当大的增强性能，通过厚度减少的基础上控制的蒸汽辅助的气固转化技术，然后与碱金属阳离子的离子交换。膜厚度的减小导致Kr渗透率从7.5大幅度增加到26.3气体渗透单位（GPU），在298 K下理想的Kr/Kr选择性>20。阳离子交换膜在环境条件或轻微低于环境条件下显示出选择性的大幅度（>50%）增加。详细研究了离子交换SAPO-34材料和膜的吸附、扩散和渗透特性，其中钾交换SAPO-34膜表现出特别有吸引力的性能。然后，我们展示了选择性SAPO-34膜上的α-氧化铝中空纤维的制造。
Separation of radioisotope Kr-85 from Xe-136 is of importance in used nuclear fuel reprocessing. Membrane separation based on zeolite molecular sieves such as chabazite SAPO-34 is an attractive alternative to energy-intensive cryogenic distillation. We report the synthesis of SAPO-34 membranes with considerably enhanced performance via thickness reduction based upon control of a steam-assisted vapor solid conversion technique followed by ion exchange with alkali metal cations. The reduction of membrane thickness leads to a large increase in Kr permeance from 7.5 to 26.3 gas permeation units (GPU) with ideal Kr/Xe selectivities >20 at 298 K. Cation-exchanged membranes show large (>50%) increases in selectivity at ambient or slight subambient conditions. The adsorption, diffusion, and permeation characteristics of ion-exchanged SAPO-34 materials and membranes are investigated in detail, with potassium-exchanged SAPO-34 membranes showing particularly attractive performance. We then demonstrate the fabrication of selective SAPO-34 membranes on alpha-alumina hollow fibers.