Colloidal silica particles, grown on a mesoporous silica layer using macroporous alumina substrate as a support, were used to separate hydrogen from carbon dioxide. The particles transformed into rectangular interlocking silicalite-1 structures with size approximately 8 x 4 x 4 mu m, oriented epitaxially with film thickness of ca. 22 mu m. The silicalite-1 particles grew in size due to the effect of structure directing agent (SDA), Oswald ripening and hydrothermal synthesis that promoted the growth of the colloidal particles into crystals. Permeation experiment using silicalite-1 showed that CO2 flux decreased and H-2 flux increased with increase in temperature. The separability of H-2 that was unity at the lower temperature became increased in value as the temperature was raised. (C) 2010 Elsevier B.V. All rights reserved.