Natural zeolite-based cement composite membranes for H2/CO2 separation

Natural zeolite-based membranes have shown promise in the separation of H-2 from CO2 and hydrocarbons. However, these highly dense, naturally monolithic materials can suffer defects, which disrupt the continuity of the zeolite micropores and create leak paths through the membrane. Cement materials were explored as a component to generate natural zeolite-based cement composite membranes because of their ability to intergrow between the zeolite particles. The influence of operating pressures and temperatures on the performance of the natural zeolite-based cement composite membranes was examined. Gas permeation tests indicated that permeation through the membrane (thickness of 1.8-2.2 mm) was an activated diffusion process and the experiments measured a hydrogen permeance of 4.1 x 10(-8) mol m(-2) s(-1) pa(-1) and a H-2/CO2 single gas selectivity of 25 at 25 degrees C and 100 kPa. (C) 2011 Elsevier B.V. All rights reserved.