Progress in Filtration and Separation

3. Pervaporation Membranes

Membrane preparation techniques and methods used to deposit thin layers upon a support have been discussed thoroughly by Mulder (1996). Membranes used in pervaporation are usually dense or microporous asymmetric polymeric membranes, which allow a high flux in combination with a high selectivity (and thus, a high PSI). They have an asymmetric or composite structure: a thin microporous top layer and a porous sublayer made from the same or a different material. The first layer enables an effective separation while maintaining a high flux. The second sublayer gives the membrane the desired mechanical strength. It can be a single plate, tube, hollow-fibre or honeycomb structure. The major requirement for the sublayer is that ...