THE DECLINING AFFINITY OF MICROPOROUS HYDROTALCITE-SILICA MEMBRANE FOR CARBON DIOXIDE

Abstract

Single permeation test reveals that excessively high sintering temperature caused unnecessary bloating and collapse of micropores to form meso- and macropore structures. It also caused reduction in carbon dioxide adsorption capacity as a result of diminishing affinitive hydrotalcite phase in the pore structures. The carbon dioxide permeance was higher than that of hydrogen, indicating affinity had greater effect than the diffusivity and molecular sieving. This is also evident from the direction of the carbon dioxide permeance that decreased with increasing sintering temperatures, confirming the dominating surface adsorption mechanism over the ordinary gas diffusion in the membrane within the operating boundaries.