Application of Mixed Matrix Membranes for Bioethanol Separation

Abstract

The production of renewable fuels have received great attention due to the problematic effects of non-renewable fuels on environment. The purification of ethanol is very important for obtaining fuel grade ethanol, but the conventional strategies for transforming bio-mass to biofuels are very energy-intensive and expensive. During fermentation, the concentration of ethanol is normally up to 1-15% based on biomass source. The water content for fuel grade ethanol should be limited to 1-3 wt. %. Distillation technique for ethanol separation from fermentation broths is commonly utilized. Furthermore, this strategy is very energy consuming and open the doors of certain other strategies like gas stripping, adsorption, ozonation etc. Hydrophobic pervaporation is another methodology used for the separation of water/alcohol mixtures. Pervaporation is a separation mechanism based on the membrane in which the feed is injected in the form of fluid and a vapor are obtained as permeate. Due to the trade-off between flux and selectivity, polymer membranes and inorganic membranes are not generally adopted. A novel In-situ approach is used to fabricate ZIF-8 /Polyimide mixed matrix membrane (MMMs) with outstanding permeability. With its high hydrophobicity ZIF-8 can provide an appropriate pore structure for the recovery of the organic compounds. Different characterization techniques were adopted to confirm the purity and performance of fillers and membranes. Membranes were tested on home based pervaporation unit to check the performance parameters of pervaporation.