Zeolite filled PDMS/PAN membranes for separation of low concentrated alcohol/water mixtures

摘要

When lignocellulosic biomass is used for alcohol production (2nd generation bio ethanol and higher order alcohol) the alcohol content derived by fermentation is relatively low, typically below 5 wt%. Due to, the high water content much energy is needed for the concentration of alcohol by distillation. A possible alternative for the thermal separation step is pervaporation with organophilic membranes. Zeolite membranes on ceramic tubular supports were developed [1] which are characterized by high fluxes, high selectivity and high thermal resistance. High processing costs of zeolite membranes are resulting high investment costs. For low temperature application zeolite filled polymeric membranes with high filling degree may be an economic alternative. A defined range of particle size distribution allows high silicalite contents in a hydrophobic polymeric matrix like polydimethylsiloxane (PDMS) for mixed-matrix-membranes (MMM). The desired MMM with high filling degrees and functionalized particle surfaces should combine a high permeability and selectivity.