Carbon membrane for gas separation derived from coal tar pitch

Carbon membrane, with properties superior to those typically found in polymeric materials, is a new and highperformance carbonaceous material for gas separation. Carbon membrane can be produced by carbonizing Various carbon-containing materials, such as thermosetting resin, pitch, coal, graphite and plants, under inert atmosphere or vacuum. Carbon membranes described in this paper are produced from the carbonization of a coal tar pitch precursor, which is heat-polymerized and preoxidized under different conditions. The results observed show that heat-polymerization temperature, preoxidative temperature and carbonization temperature have an important effect on the properties of the carbon membrane. Gas separation mechanisms on the carbon membrane involve Knudsen diffusion and viscous flow. The ideal separation factor of H-2/CO2 on the carbon-carbon composite membrane prepared by surface coating of carbon membrane can reach 16.2, but the mechanism of the gas separation needs to be further investigated. (C) 1999 Elsevier Science Ltd. All rights reserved.