α-Al2O3-supported ZIF-8 SURMOF membranes: Diffusion mechanism of ethene/ethane mixtures and gas separation performance

Metal-organic frameworks have been proven to offer the possibility of fabricating highly permeable and selective membranes. ZIF-8 is one of the most studied, attractive, and promising candidates given its known thermal stability and small pores connected by narrow sized windows of around 3.4 Å.In this paper, liquid phase epitaxial (LPE) layer-by-layer (LBL) ZIF-8 SURMOF membranes were tested for gas separation of various binary feed mixtures of ethene/ethane (C2H4/C2H6) using the Wicke-Kallenbach technique. Permeation experiments of ethene or ethane in the presence of sweep gas were also conducted. A simulation program based on the generalized Maxwell-Stefan model was also used to analyze the separation performance of the SURMOF film in more detail. Its implementation consists in a discretization of the membrane, using then experimental and literature data in order to simulate the molar fluxes.