Separation of binary, ternary and multicomponent organic/water mixtures

In this paper, the separation characteristics of polyvinyl alcohol membranes are compared for pervaporation of binary, ternary and multicomponent organic/water mixtures. The analyses were performed as a function of composition at steady-state operating conditions. Results are compared in terms of difference in permeation rate, separation factor, time taken for dehydration and temperature drop across the membrane for the three systems. The separation ability of the membrane is expressed in terms of permeation rate and selectivity. From the results, we found that the permeation rate increased and the separation factor decreased as the water concentration in the feed increased. Furthermore, we noted that the presence of one component affects the rate of transfer of the other. These results confirm that interaction between the feed, the permeate and the polymer plays an important role in pervaporation. For binary and ternary systems, permeate composition remains relatively constant over a wide range of feed concentrations, and, for the multicomponent system, water concentration in the permeate decreases as more alcohol molecules are sorbed into the membrane.