Synthesis and properties of Na-ferrierite tubular membrane formed on macroporous α-Al2O3 support by conventional and vacuum-assisted secondary growth

Using pyridine as template, polycrystalline Na-ferrierite membrane with thickness of about 30 μm was prepared successfully on macroporous α-Al2O3 support in a short crystallization time by conventional and vacuum-assisted secondary growth. The effects of synthesis parameters such as template, alkalinity and dilution were investigated. The characterization and properties of Na-ferrierite membrane prepared using parent gel with molar composition of 1Al2O3:60SiO2:6Na2O:1835H2O:64C5H5N were detected. The three-stage synthesized Na-ferrierite membrane had the best properties with the single-gas permeances of H2 > CH4 > O2 > N2 > CO2 > C3H8 > SF6. The separation properties of Na-ferrierite membrane were evaluated by benzene/p-xylene pervaporation test. With increasing the benzene feed concentration, the fluxes of benzene and p-xylene increased and decreased, respectively, and the separation factor decreased firstly and increased afterward. Furthermore, the formation mechanism of the compact Na-ferrierite membrane was proposed.

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► The vacuum-assisted secondary growth method was first introduced in this paper.
► The cost of synthesis was reduced.
► The gas permeances and fluxes of membranes were larger than that in the literatures.
► The formation mechanism of the Na-ferrierite membrane was proposed first time.