Use of the composite membrane of poly(ether-block-amide) and carbon nanotubes (CNTs) in a pervaporation system incorporated with fermentation for butanol production by Clostridium acetobutylicum.

Fermentation incorporated with pervaporation was regarded as an efficient way to relieve the feedback inhibition of butanol in acetone-butanol-ethanol (ABE) fermentation. The addition of CNTs (carbon nanotubes) to PEBA (poly(ether-block-amide)) could greatly enhance the removal flux of solvents (acetone, butanol and ethanol) in a model solution test. The butanol removing rate results in a 61% increase in the batch with PEBA+CNTs (5%) membrane compared with that of the batch with PEBA alone. Besides the increase of removal flux, the addition of CNTs enforces the mechanical strength of the pervaporation membrane, which leads to more resistance for a longer operational time. The combination of a 5-L fermenter with the pervaporation membrane of PEBA+CNTs (10%) indicates a 20% increase both in productivity and yield compared to using PEBA. In conclusion, the addition of CNTs to a PEBA pervaporation membrane has great potential when applied in the ABE fermentation industry.