High-performance NaA zeolite membranes supported on four-channel ceramic hollow fibers for ethanol dehydration

Abstract

NaA zeolite membranes were prepared on an external surface of novel four-channel α-Al₂O₃ hollow fiber (4CF) supports for pervaporation dehydration of ethanol. The 4CF supports were first seeded with ball-milled NaA zeolite seeds by a dip-coating approach and followed by hydrothermal crystallization at 100 °C for 4 h. Influences of the seeding condition and microstructure of the 4CF supports were extensively investigated. The separation performances of the as-synthesized membranes were evaluated by pervaporation dehydration of 90 wt% ethanol/water mixtures at 75 °C. A notably high water permeation flux of 12.8 kg m⁻² h⁻¹ and a separation factor of >10 000 was obtained in the membrane supported on 4CF which had a porosity of 55% as well as a high mechanical strength of 18 N. In comparison with single-channel α-Al₂O₃ hollow fiber supported NaA zeolite membranes, the 4CF supported membranes were considerably superior in permeation flux, mechanical strength and convenience of seeding operation. Allowing for high reproducibility as well as high performance, there would be great potential in industrial applications for 4CF-supported NaA zeolite membranes.