Nanofiltration by porous inorganic membranes.

Nanofiltration by porous inorganic membranes is reviewed from the viewpoint of preparation methods as well as the applications. Sol-gel methods have been widely applied to fabricate porous inorganic membranes, and alumina, titania, zirconia and silica-zirconia have been successfully applied to fabricate inorganic membranes having nanofiltration performance.Summarized are also other preparation techniques including pyrolysis of polymeric membranes, organic/inorganic hybrid membranes, hydrothermal method for zeolite membranes, anodic oxidation, dynamic membranes, clay membranes. Applications of inorganic membranes reviewed are categorized into separation of electrolytes, nanofiltration of organic solutions, electro-ultrafiltration and membrane reactor application.