Separation membranes based on porous crystalline materials are promising energy-efficient alternatives to conventional separation processes.1
They can find industrial use provided their high fabrication cost can be reduced and/or performance can be further improved. One approach is membrane fabrication based on 2-dimensional nanosheet MFI materials, which allow to fabricate thin and defect-free membranes, resulting in high throughput per unit cost.2
We have developed a direct synthesis method of MFI nanosheets, which can be used to fabricate thin and defect-free high-performance separation membranes.3
Use of seed crystal enabled the preparation of single MFI nanosheets without orthogonal twinning, yielding ~2 um lateral dimension and predominantly 5-nm thickness. These high-aspect-ratio MFI nanosheets effectively cover the surface of the porous supports and form high-density seed coating layers, which are further intergrown into continuous membranes. Resultant MFI membranes exhibit unprecedented combination of high permeance and high selectivity for xylene isomer separation (p
-xylene binary mixture), which are consistent with our theoretical calculations. Microstructure analyses established the MFI membranes fabricated from the MFI nanosheets possess favorable properties, such as thin, wide and well intergrown b
-axis-oriented grains. Permeation properties of the membranes assessed under various temperature and feed pressure conditions will be presented.
1. Gin, D. L.; Noble, R. D. Science 2011, 332, 674-676.
2. Tsapatsis, M. Toward High-Throughput Zeolite Membranes. Science 2011, 334, 767â768.
3. Jeon, M. Y.; Kim, D.; Kumar, P.; Lee, P. S.; Rangnekar, N.; Bai, P.; Shete, M.; Elyassi, B.; Lee, H. S.; Narasimharao, K.; Basahel, S. N.; Al-Thabaiti, S.; Xu, W.; Cho, H. J.; Fetisov, E. O.; Thyagarajan, R.; DeJaco, R. F.; Fan, W.; Mkhoyan, K. A.; Siepmann, J. I.; Tsapatsis, M. Nature 2017, 543, 690â694.