Pertraction, also defined as the extraction and transport through liquid membranes, consists in the transfer of a solute between two aqueous phases of different pH values or other chemical properties, phases that are separated by a solvent layer of various sizes. Pertraction efficiency and selectivity can be significantly enhanced by adding one or more carriers, such as organophosphoric compounds, long‐chain amines, or crown ethers, into the liquid membrane, the separation process being called
facilitated
or
synergic pertraction
.
Compared to the physical or reactive liquid‐liquid extraction, the pertraction method reduces the loss of solvent during the separation cycle, needs small quantity of solvent and carrier due to their continuous regeneration, and offers the possibility of solute transport against its concentration gradient as long as the pH gradient between the two aqueous phases is maintained.
In this context, this article overviews representative applications of pertraction for separating individually or selectively the biosynthetic products of carboxylic acids, amino acids, antibiotics, and vitamins. The main influences of the operating parameters on pertraction efficiency, the optimum separation conditions, and the models describing the behavior of pertraction systems are discussed in direct correlation with the practical potential of this separation technique for biotechnology.