Separation of alcohol aqueous solution by pervaporation using asymmetric polyimide membrane

Abstract

Asymmetric polyimide membranes were prepared by the phase inversion process by casting solutions composed of 25 wt% aromatic polyimide (PI-2080), 35 wt% N,N'-dimethyl formamide (DMF) and 40wt% dioxane. The membranes were annealed at 300C for 3 h in a vacuum oven and were measured for various alcohol aqueous solutions in pervaporation. The membrane exhibited separation factors of a(H₂0/EtOH) = 900 and a(H,0/2-PrOH)= I I000 with a flux of 0.45 kgm ² h t for a 95 vol.% alcohol aqueous solution at 60C. The membrane showed stable membrane performance for 3 months for a 95 vol.% ethanol aqueous solution at 60"C.