Mixed Matrix Membranes from Nanostructured Materials for Gas Separation

This work describes the preparation, characterization and application of mixed matrix membranes made from inorganic phase Nu-6(2) and Matrimid® polyimide. Due to the hydrophobic character of both the zeolitic phase (with a high Si/Al ratio of 45) and the polymer, membranes obtained are free of interfacial voids, as observed by SEM characterization and inferred from the membrane performance. Gas permeation tests carried out for the 50/50 H2/CH4 binary mixture revealed a significant enhancement of H2 separation. H2 permeability and H2/CH4 separation selectivity for the bare polyimide membrane were 32 Barrer and 118, whereas the Matrimid®-Nu-6(2) mixed matrix membrane reached a permeability of 49 Barrer and a selectivity of 206 with a zeolite content of 15%. This superior performance of the hybrid membrane is attributed to the molecular sieve role played by the selected zeolitic phase which has two different types of eight-membered-ring channels with limiting dimensions of 2.4 and 3.2 Å. © 2008 Elsevier B.V. All rights reserved.