Polyelectrolyte multilayer membranes for pervaporation separation of aqueous-organic mixtures Original Research Article

Composite membranes for pervaporation of water/alcohol mixtures were prepared by consecutive alternating adsorption of poly(acrylic acid) (polyanion) and poly(ethylenimine) (polycation) on a polyamide-6 substrate. The influence of preparation conditions on the pervaporation separation properties of polyelectrolyte multilayer composite membranes was studied. Variation of polyelectrolyte concentration of the dipping solution and adsorption time had only a minor effect on the membrane performance. On the other hand, high molecular weight polyelectrolytes had a high impact on membrane performance. A separation factor α of 2500 was observed for a membrane having four double layers. Best results were obtained when the adsorption temperature was raised from 25°C to 80°C A membrane with two double layers showed a separation factor α of 900.