Chapter 10 - 10.1 Porous Ceramics for Filtration

Abstract

This chapter summarizes the present status and a potential application of porous ceramics as materials for membrane separation. Porous ceramic membranes have great potential for opening new types of applications to which polymeric membranes cannot be applied. Membrane separation processes can be categorized based on the phases of the feed and permeate, as well as the types of driving force for the separation. The separation mechanism is mainly controlled by the sieving effects, where solutes that are smaller than the pore sizes of membranes permeate through the porous membranes. Porous membranes must have pores that are connected continuously from the feed stream to permeate stream, otherwise no permeation through the membranes is possible. Membrane performance for liquid-phase separation can be evaluated by two parameters: permeability (Lp) and rejection (R). Inorganic microfiltration and ultrafiltration membranes have been used in a wide variety of processing. The preparation of porous ceramic membranes, which need to have uniform pore sizes, to be as thin as possible without defects, seems to represent a different strategy from conventional preparation of ceramic bulk bodies. This new research field of ceramic processing will contribute much to the development of membrane science and technology.