Pervaporation

Pervaporation is a membrane separation process that removes one or more components from a liquid mixture by allowing them to pass through a selective membrane and evaporate on the other side, combining permeation through the membrane with evaporation into a vapor. Although the basic phenomenon was studied earlier in the twentieth century, practical industrial pervaporation did not arrive until the German company GFT, Gesellschaft fuer Trenntechnik, developed and commercialized membranes and equipment in the early 1980s, chiefly to dehydrate ethanol past the point where ordinary distillation alone can separate it from water. Pervaporation is now used industrially wherever a small amount of one liquid must be efficiently removed from another, particularly for solvent dehydration and for removing trace organic compounds from water.