CO 2 -philic WS 2 laminated membranes with a nanoconfined ionic liquid

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2018, Vol.6 (34), p.16566-16573
• Main Authors: Chen, Danke, Wang, Wensen, Ying, Wen, Guo, Yi, Meng, Donghui, Yan, Youguo, Yan, Rongxin, Peng, Xinsheng
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/C8TA04753G

The modern global climate change and global warming of Earth make it an urgent need to develop emerging CO 2 capture and storage techniques. Herein, we first reported the use of WS 2 nanosheets to construct laminated membranes for CO 2 separation. However, the WS 2 membrane showed poor CO 2 separation performance with Knudsen selectivities for N 2 /CO 2 (1.28), CH 4 /CO 2 (1.72) and H 2 /CO 2 (4.96). To improve the performance, an ionic liquid (IL) 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM][BF 4 ]) with high CO 2 solubility and practically no vapour pressure was used for filling the nanochannels of the WS 2 membrane. Compared to the bulk IL, the nanoconfined IL exhibits higher freezing temperature, shift of vibration bands and higher interaction energy between CO 2 and ILs. Besides, the prepared WS 2 laminated membrane with the nanoconfined ionic liquid shows excellent selectivities for CO 2 /N 2 (153.21), CO 2 /CH 4 (68.81) and CO 2 /H 2 (13.56) in single gas measurements as well as good CO 2 permeance due to the nanoconfinement of the IL. The simulation results further confirmed and explained the CO 2 separation mechanism. It indicates that the nanoconfinement of ILs into the nanochannels of two-dimensional materials is a novel way to achieve CO 2 -philic membranes to efficiently separate CO 2 from other light gases.