Synthesis of SAPO-34 Molecular Sieve Membranes by Steam-assisted Conversion Seeding and Their Characterization

A new seeding method, the steam-assisted conversion seeding, was used to prepare the high-quality SAPO-34 molecular sieve membranes by secondary growth method on the low cost macroporous α-Al2O3 sup- ports. The seeds with different sizes of 2 μm, 1 μm, 500 nm, and 100 nm were mixed in the synthesis solution to prepare the seeds-containing pastes which was coated on the surface of the support. The effects of the particle size on the paste layers, seed layers and membranes were investigated. A perfect seed layer was formed and ef- fectively modified the defects of the macroporous α-Al2O3 support and then, induced a continuous, compact and unconspicuousl pinholes SAPO-34 membrane. The SAPO-34 membrane displayed high performance in the per- vaporation dehydration of 90wt% IPA/water mixtures at 348 K, showing water flux up to 1.396 kg/(m 2 ·h) and separation factor at 973.