Polydopamine-based superhydrophobic membranes for biofuel recovery

The development of renewable energy sources like biofuels has emerged as a promising road to resolve future energy supplies. Fermentation is a common process for producing biofuels from biomass, and the biofuels have to be extracted and concentrated from the fermentation broth before they can be used. In comparison with conventional separation methods such as distillation and adsorption, membrane-based separation has been considered to be the most promising alternative because of its low energy consumption, ease of operation, and cost effectiveness. Hydrophobic polymeric membranes and inorganic membranes have been developed for recovery of bioalcohols from diluted fermentation broths via pervaporation. However, the separation performances of the previously reported hydrophobic membranes are usually unsatisfactory for the recovery of bioalcohols. It is desired to develop a novel hydrophobic membrane for efficient recovery of bioalcohols. Inspired by the adhesive ability of dopamine and the hierarchical structure of a lotus leaf, superhydrophobic membranes are developed to concentrate bioalcohols. The superhydrophobic membranes with a water contact angle of about 172.0° show a promising application for the recovery of bioalcohols from dilute aqueous solutions due to the superhydrophobicity and 0.2 μm thickness of the membrane, which offers a high potential application for in situ recovery of bioalcohols.