A Uniformly Oriented MFI Membrane for Improved CO2 Separation

Abstract

AbstractMembrane separation of CO2 from natural gas, biogas, synthesis gas, and flu gas is a simple and energy‐efficient alternative to other separation techniques. But results for CO2‐selective permeance have always been achieved by randomly oriented and thick zeolite membranes. Thin, oriented membranes have great potential to realize high‐flux and high‐selectivity separation of mixtures at low energy cost. We now report a facile method for preparing silica MFI membranes in fluoride media on a graded alumina support. In the resulting membrane straight channels are uniformly vertically aligned and the membrane has a thickness of 0.5 μm. The membrane showed a separation selectivity of 109 for CO2/H2 mixtures and a CO2 permeance of 51×10−7 mol m−2 s−1 Pa−1 at −35 °C, making it promising for practical CO2 separation from mixtures.