Asymmetric Membrane

For almost all the membrane process, flux is one of the essential process parameters. The advantages associated with high flux are small membrane area and efficient system footprint. These two factors are often considered by chemical engineers or managers in their decision-making about setting up processes using membrane separation. The thinner the required membrane structure, the higher the membrane flux. However, mechanical strength will be reduced with decreasing membrane thickness.

One of the solutions to this problem was asymmetric membrane. Loeb and Sourirajan in 1963 (Loeb and Sourirajan 1964) invented integrally skinned asymmetric membrane for reverse osmosis. They are produced by non-solvent-induced liquid-liquid phase separation processes, in which the entire structures are generated in one step from one material. Phase inversion is a process wherein the thermodynamically stable polymer solution is converted into the instable one by changing dope composition. The resultant...