4. Dense membrane separation

4.1 Pervaporation

Pervaporation is a membrane separation operation in which a liquid mixture is partially fractionated by "evaporation" of a fraction of the mixture through a dense (non-porous) membrane. There is thus a phase change, and the permeate is recovered in an initial vapor form. The driving force is a difference in activity, obtained mainly by a difference in pressure, usually by creating a partial vacuum in the permeate compartment of the membrane.

The industrial applications of pervaporation are not as numerous as those of ultrafiltration or electrodialysis, although its potential is high in the agri-food sector (e.g. flavor extraction, analytical applications (electronic nose) or bioreactors). Pervaporation can usefully be coupled with distillation...