A review concerning pervaporation and vapor permeation - membrane separation techniques used to separate liquid mixtures, is presented. Examples of polymers for membranes preparation as well as performance parameters of pervaporation and vapor permeation membranes are described. In the second part of the paper applications of pervaporation and vapor permeation in the environmental protection are presented.
At the present, liquid product mixtures must fulfill the high purity requirements as well as effluents, therefore they have to be concentrated or reconditioned. In the process of product-integrated environmental protection, liquid substances should be separated specifically from the main stream, either to save raw materials, to prevent or to minimize the disposal of effluents or to recycle the by-products. Such completely or partly soluble fluid mixtures can be separated with membrane methods. Pervaporation and vapor permeation as the most well-known membrane processes for the separation of liquid and vapor mixtures allow a variety of possible application areas:
i) dewatering of organic fluids like alcohols, ketones, ethers etc.;
ii) separation of mixtures from narrow boiling temperatures to constant (azeotrop) boiling temperatures;
iii) removal of organic pollutants from water and air streams;
iv) separation of fermentation products;
v) separation of organic-organic liquid mixtures.