Permeation of pure gases through silica membranes with controlled pore structures

Abstract

The superior thermal/chemical/mechanical stability and the ability of ceramic membranes in affecting the transport rates of chemical species through their processing controllable pore structures make them very attractive for many separation problems. Highly selective microporous silica membranes with high fluxes could be prepared by sol–gel dip coating processes [1]. The structure of the thin silica layer mainly depends on the size and the shape of the silicalite polymers and their packing behavior during drying and heat treatment. Design of the pore networks has a great importance to decide the transport properties through the membrane since permeation and the permselectivity are mainly determined by the microstructure of the membrane such as pore size and distribution, porosity as well as the interaction of permeating species with pore walls.