Fouling of poly[-1-(trimethylsilyl)-1-propyne] membranes in pervaporative recovery of butanol from aqueous solutions and ABE fermentation broth

Poly[1-(trimethylsilyl)-1-propyne] (PTMSP) dense films were evaluated for n-butanol recovery from aqueous solutions and acetone-butanol-ethanol (ABE) fermentation broth. Flux decline through PTMSP dense films due to polymer compaction under vacuum conditions, relaxation in alcohol and alcohol/water mixtures, and membrane contamination are discussed. Flux decline of a PTMSP film during pervaporation of 20 g/l BuOH/water mixture was fitted to the following function, y=At-b. PTMSP films change their geometry when exposed to alcohol and alcohol/water mixtures and then dried. As a result of the relaxation process, polymer film becomes thicker and denser, effecting membrane performance. PTMSP films that were treated with 70% iso-propanol/water show linear Aux decline versus pervaporation time. Strong lipid adsorption seems to occur on the membrane surface when fermentation broth is used as a feed causing flux decline within short period of time. (C) 2000 Elsevier Science B.V. All rights reserved.