Thermopervaporative Removal of Isopropanol and Butanol from Aqueous Media Using Membranes Based on Hydrophobic Polysiloxanes

For thermopervaporational (TPV) removal of isopropanol and butanol from fermentation broths, known commercial membranes have been experimentally studied, namely, the membranes based on poly(dimethylsiloxane) (PDMS) ((Pervap 4060, Pervatech PDMS, PolyAn and MDK-3) and poly[1-(trimethylsilyl)-1-propyne] (PTMSP). The effect of isopropanol concentration and feed mixture temperature on the TPV properties of the membranes has been studied. It has been found that the most effective membrane for TPV removal of butanol from aqueous media is the PolyAn membrane (PolyAn GmbH, Germany). The membrane has shown the maximum values of permeate flux and pervaporation separation index. The PolyAn membrane has been studied in terms of TPV separation of ternary butanol–isopropanol–water mixture. It has been shown that the existing membrane materials possess low isopropanol-water selectivity (less than 1), therefore, it is necessary to find and develop novel materials promising for the given separation task.