The pervaporation of ethanol water feeds with polyaniline membranes and blends

Pervaporation experiments with ethanol/water feeds and polyaniline membranes have been performed. Undoped polyaniline is shown to be highly selective for water over ethanol, leading to selectivities (alpha) > 1,000, although permeation fluxes are low. The mechanism of permselectivity in undoped polyaniline is shown to be controlled by the high diffusivity selectivity for water. Hydrochloric acid-doped polyaniline membranes suffer from the effect of HCl-dopants leaching from the membrane into the feed. The use of polymeric dopants, such as polyamic acid and polyacrylic acid, eliminates this problem, and leads to improvements in properties compared to HCl-doped polyaniline.