Preparation and characterisation of a TiO2/α-Al2O3 nanofiltration membrane by a sol-gel method

Inorganic nanofiltration (NF) membranes have found wide application in water and wastewater treatment due to their good chemical and thermal stabilities. A TiO2 NF membrane was prepared successfully by sol-gel method with an alpha-Al2O3 membrane as a support. The sol of high quality was firstly prepared with tetrabutyl titanate as a precursor, anhydrous ethanol as a solvent, acetylacetone as an inhibitor, and hydrochloric acid and ammonia as catalysts. The TiO2 NF composite membrane was then prepared with the support by dip coating method followed by sintering. The microstructure and surface composition of the composite NF membrane were investigated by SEM and XRD analyses. The results indicated that there existed an unbroken TiO2 NF layer on the support. The experiments of molecular weight cut-off (MWCO) and salt retention for the TiO2 NF membrane were also conducted. The results show that the NF membrane has been prepared successfully.