Seeding-free synthesis of zeolite FAU membrane for seawater desalination by pervaporation

In this study, dense and phase-pure zeolite FAU membrane has been prepared on α-Al₂O₃ tube using a seeding-free synthesis strategy. 3-aminopropyltriethoxysilane (APTES) acts as a molecular linker for anchoring the FAU precursors onto the support surface to promote the nucleation and the formation of a thin, well intergrown zeolite FAU membrane. The obtained membranes are employed for desalination of seawater by pervaporation. With the increase of the synthesis time from 12 h to 24 h at 75 °C, the water fluxes of the zeolite FAU membranes reduce from 4.22 kg m⁻² h⁻¹ to 3.42 kg m⁻² h⁻¹ at 75 °C due to the increase of the thickness of the zeolite FAU membranes, while the ions rejections increase from 99% to 99.9%. For the zeolite FAU membrane which was prepared at 75 °C for 20 h, with increasing the feed temperature from 30 °C to 90 °C, the water fluxes increase from 0.96 kg m⁻² h⁻¹ to 5.64 kg m⁻² h⁻¹, and all the ions rejections of the zeolite FAU membrane are above 99.8%. Note that the zeolite FAU membranes show high separation performances for seawater desalination, even for desalination of 10 wt% seawater, the developed zeolite FAU membranes are very promising in seawater desalination.