3- pervaporation is used to purify a 95 wt% ethanol in water feed. the operating pressure on the permeate side of the membrane is 25 mm hg. the temperature on the feed side of the membrane is 80 °c. under these conditions the flux of permeate (ethanol + water) is 0.25 kg/m2.h and composition of the of ethanol in permeate is 7.5 wt%.