In-situ recovery of bio-butanol from glycerol fermentation using PDMS/ceramic composite membrane

Pervaporation (PV) membranes have been attracted increasing attention in biofuels recovery owing to the higher separation efficiency and less harmful effect on microbes. Herein, we reported polydimethylsiloxane (PDMS) membrane coated on the inner surface of ceramic tube to in-situ recover bio-butanol from glycerol fermentation through PV process. The effects of butanol concentration, intermediates, raw material, inorganic salts and microbes on PV separation property of the PDMS/ceramic composite membranes were systematically discussed. After integrating with the membrane, bio-butanol was successively extracted from the fermentor, thereby remarkably reducing the butanol inhibition effect on microbial growth and thus greatly enhancing the yield and productivity of bio-butanol, from 0.35 to 0.40 g g⁻¹ and 0.09 to 0.17 g L⁻¹ h⁻¹, respectively. Meanwhile, the PDMS composite membrane presented an excellent separation property during the coupled process with 509 g/m² h for average total flux and 24.7 for butanol/water separation factor. In addition, the membrane fouling behavior was studied by characterizing the membrane microstructure and chemical property before and after using in the coupled process. Compared with the-state-of-the-arts, the PDMS composite membrane coupled with the process of glycerol fermentation presented here shows great potential in application of bio-butanol production.