(2a) Pervaporative Recovery of Butanol From Fermentation Broth Using Mixed Matrix Membranes

Butanol is a promising alternative fuel, with many properties comparable to those of gasoline. However, butanol production by acetone-butanol-ethanol fermentation is limited by end-product inhibition at low solvent concentrations. Butanol production could be greatly enhanced if fermentation is coupled with product removal. This study focuses on the selective extraction of butanol from fermentation broth using mixed matrix pervaporation membranes. The separation properties and structure of thin-film pervaporation membranes consisting of ZSM-5 zeolites dispersed in a poly(dimethylsiloxane) (PDMS) polymeric matrix are analyzed. Specifically, the effect of zeolite hydrophobicity, as measured by the SiO₂:Al₂O₃ ratio in the zeolite framework, is investigated.