Polymers for Butanol Pervaporation Membranes

While ethanol is the biofuel produced today in by far the greatest quantity, it has substantial limitations: most notably, it cannot serve as a drop-in replacement for gasoline in standard engines, nor can ethanol be transported in the piping used today for gasoline because of its higher water absorption and corrosiveness. On the other hand, isomers of butanol—especially n-butanol and isobutanol, both of which can be produced by fermentation (biobutanol)—are far more similar in their properties to gasoline, are less corrosive, and will burn in conventional engines even at 100% butanol. However, both butanol isomers are highly toxic to the organisms that produce them, limiting the concentration of butanol in the fermentation broth to ~1%, more typically 0.5%. If distillation is used to recover the butanol from even a 1% broth, more energy is required for the separation than is subsequently generated by combustion of the butanol. Preserving the carbon neutrality and reasonable cost of biobutanol thus mandates an alternative separation process. One of the most promising is pervaporation, where a membrane separates a gaseous permeate from a liquid feed; the butanol-rich permeate is subsequently condensed. Continuous removal of butanol through a pervaporation membrane would allow maintenance of the butanol concentration in the fermentor below the toxic level, permitting continuous operation and increasing productivity.

We propose to synthesize block copolymers consisting of a butanol-transporting block, and a matrix block having a high glass transition temperature, and to evaluate these materials for butanol pervaporation. This project was launched in mid-2014 as one of the inaugural projects of the Innovation Fund for Industrial Collaborations, created by Princeton University’s Dean for Research, and is a collaboration with chemists and engineers at Promerus LLC. Check this webpage later, as our findings become available for distribution! In the meantime, please read the Princeton University press release.

Supported by Promerus LLC and the Princeton University Innovation Fund for Industrial Collaboration

Current/Recent Group Members, and Their Project Titles:

Dong-Gyun Kim PDRA - "Novel Block Copolymers for Butanol Pervaporation Membranes"