Facile preparation of compact LTA molecular sieve membranes on polyethyleneimine modified substrates

A facile preparation strategy was proposed for preparation of compact zeolite LTA membranes on polyethyleneimine (PEI) modified substrates without seeding. Through the functionalization of substrates by using PEI, compact LTA membranes can be formed on various kinds of substrates. A well-intergrown and phase-pure LTA membrane with a thickness of about 3.0 μm is successfully prepared on the α-Al₂O₃ disk after crystallization for 24 h at 60 °C. Besides LTA membrane, well-intergrown zeolite FAU membranes can also be formed on PEI-modified α-Al₂O₃ substrates, suggesting the universality of this strategy. The zeolite LTA membranes synthesized on PEI-modified α-Al₂O₃ tubes were evaluated for the separation of alcohols/water mixture through pervaporation. The as-synthesized zeolite LTA membranes display high pervaporation performances. For the separation of 10 wt% iso-propanol/water solution at 90 °C, a high separation factor of 44991 and a water flux of 1.73 kg m⁻² h⁻¹ are achieved.