EVALUATION OF PTMSP MEMBRANES IN ACHIEVING ENHANCED ETHANOL REMOVAL FROM FERMENTATIONS BY PERVAPORATION

The use of membrane processes for the recovery of fermentation product s has been gaining increased acceptance in recent years. Pervaporation has been studied in the past as a process for simultaneous fermentati on and recovery of volatile products such as ethanol and butanol. Howe ver, membrane fouling and low permeate fluxes have imposed limitations on the effectiveness of the process. In this study, we characterize t he performance of a substituted polyacetylene membrane, poly[(1-trimet hylsilyl)-1-propyne] (PTMSP), in the recovery of ethanol from aqueous mixtures and fermentation broths. Pervaporation using PTMSP membranes shows a distinct advantage over conventional poly(dimethyl siloxane) ( PDMS) membranes in ethanol removal. The flux with PTMSP is about three fold higher and the concentration factor is about twofold higher than the corresponding performance achieved with PDMS under similar conditi ons. The performance of PTMSP with fermentation broths shows a reducti on in both flux and concentration factor relative to ethanol-water mix tures. However, the PTMSP membranes indicate initial promise of increa sed fouling resistance in operation with cell-containing fermentation broths.