Pervaporative separation of bioethanol using a polydimethylsiloxane/polyetherimide composite hollow-fiber membrane

Pervaporation is one of the most promising separation processes for the purification of ethanol. In this study, a composite hollow-fiber membrane with a thin polydimethylsiloxane (PDMS) active layer on a polyetherimide (PEI) macroporous support was used for pervaporative separation of ethanol produced by Saccharomyces cerevisiae from glucose fermentation broth. The pervaporation performance for ethanol/water binary mixtures was strongly dependent on the feed concentration and operating temperature for ethanol concentrations of 1-10%. The composite hollow-fiber membrane was stable over the long-term (about 160 days) with an ethanol permeation flux of 60-62 g/m(2)h and a separation factor of 7-9. In comparison with published results for PDMS composite membranes, the PDMS/PEI hollow-fiber composite membrane had relatively good pervaporation performance with a total flux of 231-252 g/m(2)h.