Gas Permeability Properties of Mixed-Matrix Matrimid Membranes Containing a Carbon Aerogel: A Material with Both Micropores and Mesopores

Abstract

A carbon aerogel was prepared by carbonizing a resorcinol−formaldehyde polymer gel at 800 °C. Nitrogen adsorption shows the obtained carbon aerogel has both micropores (0.54 nm) and mesopores (2.14 nm). Matrimid mixed-matrix membranes containing the carbon aerogels were successfully prepared and evaluated for the permeation of H2, N2, O2, CH4, CO2, and gas mixtures. The ideal selectivity of H2/N2, CO2/CH4, and O2/N2 gas pairs increased from 79.6, 34.5, and 6.6 for pure Matrimid to 111, 47.8, and 9.1 at 20% loading, respectively. These results suggest that the polymer chains can penetrate the carbon mesopores to achieve good contact between the carbon aerogel and Matrimid, while the micropores may provide size and shape selectivity.