Pervaporation Composite Membrane for Aqueous Solution Separation for Biofuels

University of Connecticut
posted on 07/27/2010

• request more info 
•   
•  LICENSE ONLINE

Biofuels and biomass-derived organic chemical materials provide significant benefits as renewable energy. N-butanol is a promising biofuel to replace gasoline. Several microorganisms produce n-butanol by fermentation, however, during fermentation, accumulated n-butanol can be toxic for the microorganisms and can limit the yield and efficiency of the process. Extraction or separation of the n-butanol during the fermentation is desirable because it can increase batch life or allow for continuous operation. Pervaporation is an alternative to the more costly distillation process used to separate organic components from the aqueous mixtures. In the pervaporation process, the fermentation broth is brought into contact with a membrane which allows the organic n-butanol component of the aqueous fermentation mixture to preferentially permeate the membrane. This permeate is then removed as a vapor from the downstream side of the membrane film. The efficiency of the membrane used for pervaporation is critical to the success of the whole process and is measured by its flux and separation factor.

Dr. Richard Parnas developed a new composite pervaporation membrane comprised of polyethylene (PE) and polydimethylsiloxane (PDMS) layers. Pairing the PDMS layer with a porous PE layer enhances the n-butanol flux through the membrane from 33% to 293%, depending on operating conditions. A similar increase is observed in the separation factor. The advantage of this membrane design is that it is very easy to construct from inexpensive components. The membrane can have various shapes and thickness, also, it could be used for separations of various organic components from aqueous streams, for example, fermentation mixture, ground water, recycle streams for various processes etc.

-Biofuel separation
-Water disposal
-Separation of organic components

-high efficiency
-inexpensive materials