Butanol has shown potential as an alternative biofuel. It can be obtained through ABE fermentation, which produces 1-butanol, ethanol and acetone. Pervaporation is a potential separation process, since it can be successfully applied to remove trace components such as butanol, which is toxic to the cells. The development of an effective membrane is the limiting factor for this technology. Activated carbon-containing polydimethylsiloxane membranes were prepared by varying the filler content up to 2 wt%. The resulting membranes were characterized for the separation of model solutions with 1-butanol, acetone, ethanol and water by pervaporation. The effects of activated carbon load (0, 1, 2 wt%) and temperature (25, 40, 55ºC) on flux and separation factor were evaluated. The addition of 1 wt% activated carbon increased membrane free volume, changed surface morphology and showed flux of 45 g/m2h, with separation factor for 1-butanol of 370, at 55ºC.

Polydimethylsiloxane (PDMS) membranes with different concentrations of multi-walled carbon nanotubes were prepared in order to evaluate their gas separation performances. Mixed matrix membranes were characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transformed infrared, positron annihilation lifetime and Raman spectroscopies and X-ray diffraction. The permeabilities to CO2, CH4, N2 and O2 were determined. No phase separation was noticed. For carbon nanotubes content of 1 wt%, it was shown a decrease in membrane permeability with slight increase in ideal selectivity, compared to pure PDMS. However, the increase in the filler load up to 6.7 wt% increased the free volume average size of the membranes, improving the contribution of the diffusion to the transport and decreasing ideal selectivities of CO2/CH4, CO2/N2 and O2/N2.

Polyurethane/multi-walled carbon nanotube (MWCNT) nanocomposites have been prepared with nanotube concentrations between 0.01 wt% and 1 wt%. MWCNT as-synthesized samples with ~74 nm diameter and ~7 μm length were introduced by solution processing in the polyurethane matrix. Scanning electron microscopy (SEM) images demonstrated good dispersion and adhesion of the CNTs to the polymeric matrix. The C=O stretching band showed evidence of perturbation of the hydrogen interaction between urethanic moieties in the nanocomposites as compared to pure TPU. Differential scanning calorimetry and positron anihilation lifetime spectroscopy measurements allowed the detection of glass transition displacement with carbon nanotube addition. Furthermore, the electrical conductivity of the nanocomposites was significantly increased with the addition of CNT.