Butanol recovery from model solution/fermentation broth by pervaporation: evaluation of membrane performance

This is an overview of butanol separation from model solutions and fermentation broth by pervaporation. It is difficult to compare different authors’ work on butanol separation because of the number of variables involved. These variables include type of membrane, membrane thickness, feed temperature, condensation temperature, vacuum or sweep gas, feed butanol concentration, etc. For comparison we have calculated the butanol concentration in the permeate and butanol flux from the data given by various authors. Polytetrafluoroethylene (PTFE) membrane and polypropylene (PP) membrane pass a large amount of water through the membrane. Fermentation broth was found to decrease flux and selectivity of a liquid membrane. A silicalite membrane offers high butanol flux and high butanol concentration when using fermentation broth. A thin polydimethylsiloxane (PDMS) membrane offers high flux and low selectivity, while a thick membrane offers high selectivity and low flux.