Abstract
We have prepared porous clay membranes from the clay gels using a freezing and a vacuum drying processes. The SEM observations revealed that the membranes possess channel-like holes whose diameter in between several to several ten micrometers. The oxygen permeability and acetaldehyde absorption tests indicate that the holes are penetrated from the bottom to the top of the membrane although they have not ideal strait channels. The mechanism of the formation of the holes is proposed; the freezing process yields ice-seeds on a substrate and the seeds grow along a direction to perpendicular to the substrate. The resultant needle-ice crystals lead to formation of channel-like penetrated holes in the membrane. Furthermore, composite membranes with the penetrate holes could be prepared with ZSM-5 or mordenite particles. As the result, we have developed novel-clay-based-membranes with many penetrate holes, which widen to apply for the reactor or filter devices.
