Synthesis of NaA zeolite membranes with high water flux on macroporous Si3N4

Abstract

LTA zeolite membranes have been extensively investigated for dehydration applications. However, preparing high flux NaA zeolite membranes remains a challenge. Porous Si₃N₄ that combines high porosity with excellent mechanical strength presents a promising support material for developing such high-performance membranes. In this work, high flux NaA membranes achieved controlled fabrication on macroporous Si₃N₄ supports via a secondary growth method. A simple and efficient double layer seed-coating method was employed at variable temperature. Sufficient crystallization time promotes synthesis gel penetration into the support–seed interface, enabling anisotropic crystal growth to form mechanical interlocking between NaA membranes and β-Si₃N₄ grains. The optimal membrane showed a flux up to 5.76 kg m⁻² h⁻¹ and a separation factor of 8432 for the dehydration of 90 wt% ethanol/water at 70 °C.