Pervaporation is a method for the separation of mixtures of liquids by partial vaporization through a non-porous membrane.

The membrane acts as a selective barrier between the two phases, the liquid phase feed and the vapor phase permeate. It allows the desired component(s) of the liquid feed to transfer through it by vaporization. The separation process is mainly due to polarity difference, and not to the volatility difference of the components in the feed. The word is derived from the two basic steps of the process, firstely the permeation through the membrane by the permate, then it's evaporation into the vapour phase. This process is used by a number of industies for several different processes due to its simplicity and in-line nature.