Bio-butanol is expected to be useful as a liquid fuel because the energy density of butanol is higher than that of ethanol We developed a separation membrane that yielded an butanol concentration of 81 8 wt % from 1 wt % butanol solution by a pervaporation method The membrane is a silicone-rubber-coated silicalite on a porous support tube The butanol concentration process will be simplified greatly by the development of this membrane Refining the butanol from 1 wt % butanol solution takes 13% of the amount of energy yielded by the butanol
