High-temperature pervaporation performance of ceramic-supported polyimide membranes in the dehydration of alcohols

Ceramic-supported polymer (CSP) membranes were prepared based on Torlon, P84, and Matrimid. The dehydration performance of these membranes was determined by pervaporation of n-butanol/water mixtures (95/5 wt%) at 95 °C. Based on their performance P84 was selected for further testing. P84 membranes showed excellent separation performance in dehydration of n-butanol for at least 300 days. Different curing temperatures in the range of 70–300 °C were used. The most significant flux difference was seen for a P84 membrane cured at 300 °C, compared to the lower temperatures. The separation performance of a P84 CSP membrane at 150 °C showed water fluxes in the range of 1–6 kg/m2 h and separation factors of at least 360. The membrane life-time in n-butanol/water mixtures ranges from 80 to 140 days at 150 °C. No clear relation between curing temperature and membrane stability could be derived. Reasonable separation performance of a P84 CSP membrane in an ethanol/water mixture was demonstrated. Stable performance at 150 °C was observed for the dehydration of t-butanol up to at least 250 days.