Increasing The Performance Of Asymmetric Pervaporation Membranes For The Separation Of Methanol/Methyl-Tert-Butyl Ether Mixtures By The Introduction Of Sulfonated Polyimide Into The Poly(Amide-Imide) Matrix

A series of novel asymmetric membranes from polymer composites of poly(amide-imide) with various content of sulfonated polyimide (1-6 wt%) was obtained through the nonsolvent-induced phase separation process. Selective transport properties of the obtained materials were investigated in terms of pervaporation separation of methanol/methyl-tert-butyl ether mixtures at different temperatures. The introduction of the sulfonated polyimide to the poly(amide-imide) matrix leads to a significant increase in membrane flux and an overall decrease in the process selectivity. Composite membranes having 1 wt% sulfonated polyimide in the matrix showed increased values of membrane flux (0.960 kg m(-2)h(-1)in comparison with 0.682 kg m(-2)h(-1)for unmodified membranes at 40 degrees C, 10 wt% methanol), while having similar selectivity values (79.2 wt% methanol in permeate in comparison with 82 wt% for unmodified membranes at 40 degrees C, 10 wt% methanol). Modified membrane showed the highest separation factor of 147 while separating methanol from its 3 wt% mixture with methyl-tert butyl ether at 52 degrees C with the overall flux of 1.01 kg m(-2)h(-1). A semiempirical mathematical model was developed and applied to test the efficiency of obtained membranes in the hybrid process of methanol/methyl-tert-butyl ether mixtures separation.