A New Option: Osmotic Distillaton

tion process in which a liquid mixture containing a volatile component is contacted with a microporous, non-liquid-wettable membrane whose opposite surface is exposed to a second liquid phase capable of absorbing that component — is nearing commercialization for the concentration of beverages and other liquid foodstuffs, and is under evaluation for the concentration of aqueous solutions of thermally labile pharmaceutical products and biologicals. Its primary advantage lies in its ability to concentrate solutes to very high levels at low temperature and pressure, with minimal thermal or mechanical damage to or loss of those solutes. The process also can enable the selective removal of a single volatile solute from an aqueous solution (for instance, ethanol from wine and other ferments) using water as the extracting solvent. Low-alcohol-content beverages have been produced in this manner with minimal losses of volatile flavor and fragrance components. Osmotic distillation (OD) promises to become an attractive complement or alternative to other athermal or lowtemperature separations techniques such as ultrafiltration (UF), reverse osmosis (RO), pervaporation, and vacuum freeze drying.