Diffusive separation of propylene/propane with ZIF-8 membranes

Diffusive separation of propylene/propane with ZIF-8 membranes

Type	Journal Article
Author	Nobuo Hara
Author	Miki Yoshimune
URL	http://www.sciencedirect.com/science/article/pii/S0376738813007308
Volume	450
Pages	215-223
Publication	Journal of Membrane Science
Date	January 15, 2014
Abstract	Researchers determined the contribution of diffusive separation of propylene/propane from the permeation properties of zeolitic-imidazolate framework-8 (ZIF-8)11 ZIF, zeolitic-imidazolate framework. membranes. The membranes were fabricated with a counter diffusion method, resulting in the formation of an 80 μm-thick ZIF-8 layer on the outermost section of a porous α-alumina capillary substrate. They studied single-component gas permeation properties using helium, hydrogen, carbon dioxide, oxygen, nitrogen, methane, propylene, and propane at temperatures ranging from 298 to 363 K. The molecular sieve gas permeation properties of the ZIF-8 membranes increased with reaction time, consistent with the evolution of ZIF-8 crystal formation. The ZIF-8 membrane permeances of hydrogen and propylene reached 9.1×10−8 and 2.5×10−9 mol m−2 s−1 Pa−1, respectively. The ideal separation factors for hydrogen/propane and propylene/propane at 298 K were found to be 2000 and 59, respectively. The diffusion separation factor increased with decreasing temperature, reaching 23, while the solution separation factor remained 2.7. Researchers ascribe the separation of propylene/propane diffusive separation.