Seeding-free synthesis of oriented zeolite LTA membrane on PDI-modified support for dehydration of alcohols

A seeding-free synthesis method is developed for preparation of oriented zeolite LTA membranes by using 1,4-phenylene diisocyanate (PDI) as a molecular linker. Before hydrothermal synthesis, –NCO groups are introduced with the functionalization of Al2O3 supports by PDI. A thin, well intergrown zeolite LTA membrane with a thickness of about 4.0 µm can be formed on the PDI-modified Al2O3 supports. The zeolite LTA membrane displays high pervaporation performances for dehydration of alcohols. At 90°C, the separation factor of the zeolite LTA membrane is 4480 for dehydration of 95 wt% ethanol/water mixtures, with a high water flux of 3.4 kg·m−2·h−1.