Pervaporation of ethanol—water mixture by Co 60 γ‐ray irradiation‐modified nylon 4 membrane

The ethanol—water separation by pervaporation with γ‐ray irradiation‐modified nylon 4 membrane was investigated. The membrane was prepared by homografting γ‐ray irradiation of vinyl acetate (VAc) monomer onto nylon 4, poly(vinyl acetate) (PVAc)‐homo‐ g ‐nylon 4 followed by hydrolysis treatment, poly(vinyl alcohol) (PVA)‐homo‐ g ‐nylon 4. The homografting method shows significant improvement in the degree of grafting of (VAc) onto nylon 4 over the heterografting method. For example, the degree of grafting of the VAc with 30 vol % and total dose of 2 Mrad for the heterografted method and for the homografted method are 14.1 and 42.2%, respectively. The effects of irradiation with or without oxygen in solution, irradiation time, VAc content, degree of grafting, crystallinity, feed concentration, and operating temperature on performances of the PVA‐homo‐ g ‐nylon 4 membrane were carried out. Comparison of the separation factor of sorption in membrane (α sorp ) and that of pervaporation (α perv ) was made. A separation factor of 7.3 and a 0.691 kg/m 2 h permeation rate can be obtained by the PVA‐homo‐ g ‐nylon 4 membrane with a degree of grafting of 42.2% for 90 wt % ethanol feed concentration. Compared with the unmodified nylon 4 membrane, which has the separation factor of 4 and permeation rate of 0.350 kg/m 2 h, the PVA‐homo‐ g ‐nylon 4 membrane shows improved a separation factor and permeation rate. © 1993 John Wiley & Sons, Inc.