THE CHARACTERISTICS OF A PAA PSF COMPOSITE MEMBRANE FOR SEPARATION OF WATER ETHANOL MIXTURES THROUGH PERVAPORATION

A PAA-PSf composite membrane was evaluated for separation of water-ethanol mixtures by pervaporation, and the separation characteristics were investigated in relation to the preparation conditions of the PSf composite support and the addition of aluminium nitrate to the PAA coating solution. The composite membrane had a water permselectivity over the entire range of ethanol feed concentrations; particularly the separation factor was high at higher ethanol concentrations. The maximum separation factor was 10,800 at an ethanol feed concentration of 95 wt.%. The membranes showed a maximum separation factor with 10 wt.% PSf in the dope solution and a 10 minute gelation time. The dependence of the separation properties on the aluminium nitrate concentration in the PAA coating solution exhibited a maximum at 1/10 mass ratio.