Mass Transport through Composite Asymmetric Membranes

In recent years, membrane separation technology has emerged as efficient and promising separation process from laboratory scale applications to wide range of technical industrial applications. The development of composite asymmetric membrane is a major breakthrough in membrane research field, as this membrane offers significantly high selectivity without affecting the mechanical durability of the membranes. In this chapter, structural characteristics and different fabrication techniques of composite membranes are reviewed. Moreover the mass transfer mechanism through the composite asymmetric membrane is described in details following solution-diffusion theory, Knudsen diffusion, and series resistance model. Composite membranes are preferred over others because of the high flux and enhanced selectivity without disturbing the mechanical stability of the membranes. These membranes are now widely employed in the applications of reverse osmosis (RO), nanofiltration (NF), pervaporation, gas separation, hydrocarbon fractionations, etc. As composite asymmetric membranes are “tailor-made” in nature, membrane characteristics can be tuned accordingly depending on their end use. Therefore plentiful research opportunities still exist to elevate their performance ability in terms of stability, selectivity and fouling resistance, which will in turn augment its application domain.