Hirosawa Fumiya, Miyagawa Masaya, Takaba Hiromitsu
Graduate School of Engineering, Kogakuin University, Tokyo 192-0015, Japan.
Department of Environmental Chemistry and Chemical Engineering, School of Advanced Engineering, Kogakuin University, Tokyo 192-0015, Japan.
Membranes (Basel). 2023 Feb 26;13(3):278. doi: 10.3390/membranes13030278.
The CO permeability and selectivity of CHA-type zeolite membranes in the separation of a CO/CH mixture gas at high pressure were evaluated using non-equilibrium molecular dynamics (NEMD). It was found that in a perfectly crystalline, defect-free CHA membrane, the adsorption of CH, which diffuses slowly in the pores, hinders CO permeation. Therefore, an increase in the amount of CH adsorbed at high pressure decreases the CO permeability and significantly reduces the CO selectivity of the CHA membrane. CHA membranes with grain boundaries parallel to the permeation direction were found to show higher CO selectivity than perfectly crystalline CHA membranes at high pressure, as the blocking effect of CH on CO permeation occurring within the grain boundary is not significant. This paper is the first to show that the CO permeability of CHA membranes with controlled grain boundaries can exceed the intrinsic performance of fully crystalline zeolite membranes at high pressure.
利用非平衡分子动力学（NEMD）评估了CHA型沸石膜在高压下分离CO/CH混合气体时的CO渗透性和选择性。研究发现，在完美结晶、无缺陷的CHA膜中，在孔中扩散缓慢的CH的吸附会阻碍CO渗透。因此，高压下CH吸附量的增加会降低CO渗透性，并显著降低CHA膜的CO选择性。发现具有平行于渗透方向的晶界的CHA膜在高压下比完美结晶的CHA膜表现出更高的CO选择性，因为晶界内CH对CO渗透的阻碍作用不显著。本文首次表明，具有可控晶界的CHA膜在高压下的CO渗透性可以超过完全结晶沸石膜的本征性能。
