The term pervaporation is derived from the two steps of the process: (a) permeation through the membrane by the permeate, then (b) its evaporation into the vapor phase. This process is used by a number of industries for several different processes, including purification and analysis, due to its simplicity and in-line nature. 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. Separation of components is based on a difference in transport rate of individual components through the membrane.