Mixed matrix membranes of polydimethylsiloxane with activated carbon for ABE separation

The demand for the large-scale biofuels production is very high. The use of ethanol and butanol in flex-fuel vehicles have already been achieved, but still need improvement to decrease the gasoline-dependence. In addition to it, the preparation of ethanol and butanol by eco-friendly routes are still a challenge. The use of ABE route, in which acetone, butanol, and ethanol are prepared by fermentation of 5 or 6 carbon sugars, requires higher yields and better separation performance. The goal of this work was to evaluate the use of pervaporation through asymmetric activated carbon (AC) dispersed polymethylsiloxane membranes for the separation of ABE aqueous solution with 1 wt% total organics. The amount of the filler was varied from 0 to 3 wt%. Membranes were characterized by scanning electronic microscopy, Fourier transformed infrared spectroscopy, swelling in solvents, thermogravimetric analysis, and differential scanning calorimetry. Membrane with 1 wt% of AC membrane showed different behaviors both in thermal resistance, which was increased, and also in pervaporation separation index (PSI). In this condition, membrane total flux, separation factor, and PSI for ethanol were 13.2, 2.6, and 19.9 g m⁻² h⁻¹, so that sorption behavior and diffusion rates were changed. Thus, it was possible to modulate membrane properties.