Separation of isopropyl alcohol-toluene mixtures by pervaporation using poly(vinyl alcohol) membrane

The application of pervaporation for the removal of volatile organic compound has been fascinating for the last few years. This is due to the increasing level of petrochemical solvents in the environment. In this work performance of poly(vinyl alcohol) membrane was studied for the separation of isopropyl alcohol-toluene mixtures by pervaporation. Alcohol-aromatic mixtures are difficult to separate using conventional methods and pervaporation has been a promising technology in this case. Pervaporation properties of poly(vinyl alcohol) membrane for isopropyl alcohol-toluene mixtures were studied for feeds in composition of 10-40 wt. % toluene at different temperatures (i.e., 35-50 °C) and different pressures (i.e., 4-16 psi). For understanding membrane morphology Fourier transform infrared spectroscopy and scanning electron microscopic studies were performed. Membrane performance was studied by calculating flux, selectivity and pervaporation separation index. The maximum toluene content of 78% in the permeate was obtained at optimum conditions, i.e., 12 psi applied pressure, 40 °C temperature and 10 wt. % toluene in feed solution. The flux increased with increasing amount of toluene in the feed, but selectivity decreased reasonably.