CONCENTRATION POLARIZATION DURING THE ENRICHMENT OF AROMA COMPOUNDS FROM A WATER SOLUTION BY PERVAPORATION

Pervaporation has proved to be an interesting technique for the recovery and enrichment of aroma compounds from very dilute solutions. In order to study the mass transfer, a 0.5-ppm solution of butyl butyrate, an important aroma compound present in, for example, apple juice, was pervaporated at different circulation velocities along a PDMS (polydimethylsiloxane) membrane. The permeation of butyl butyrate increased with increasing Reynolds number, demonstrating an influence of concentration polarization. In order to minimize the effect of the polarized layer and to improve the mass transfer, optimization of the feed-circulation velocity is very important.