Structure and Separation Properties of Silica Membranes.

Microporoussilica membranes are highly suitable for gas separation processes due to their high selectivity, and high stability at enhanced temperatures and in chemically aggressive environments compared to their polymeric counterparts.Sol-gel synthesis of silica sol and coating a substrate with that sol is the best-known way to produce microporous silica membranes.The structure of silica polymers/particles in the sol is the most important parameter deciding the final properties of the membrane.In this paper, some of the reported membrane processing methods and properties are compared to elucidate the structure of the membrane pores.