Study on the reproducibility of mordenite tubular membranes used in the dehydration of ethanol

The reproducibility of the preparation of mordenite membranes by seeded hydrothermal synthesis and of subsequent alkaline post-synthetic treatments has been studied in terms of the weight (zeolite) gained or lost in the process, and of the pervaporation performance regarding water/ethanol separation factor and water flux. To attain statistically significant results, a total of 71 membranes were prepared under the same synthesis conditions. Of these, 52 (selected in view of their pervaporation performance) were subjected to hydrothermal postreatment (at 180 °C and pH 10) by immersion into different volumes (in the 31-124 mL range) of alkaline solution. Statistical analysis indicated that the post-synthetic treatment increased the dispersion of membrane performance results, especially when the membranes were treated with a higher volume of alkaline solution.