Low-temperature preparation and performance study of α-Al₂O₃ tight ultrafiltration membranes

α-Al₂O₃ has become a classic material for the preparation of ceramic membranes due to its low-cost price and excellent performance. However, α-Al₂O₃ requires high temperature to drive the phase transition, which will lead to the overgrowth of grains and aggregation of pores. In order to prepare α-Al₂O₃ ultrafiltration membranes with high permeability and small pore size, by adjusting the preparation parameters of the polymeric sol route and the heating conditions of the calcination process, an alumina polymeric sol that can complete the α-phase transition at 950 °C was prepared. Subsequently, α-Al₂O₃ ultrafiltration membranes with an ultra-thin separation layer and a defect-free α-Al₂O₃ ultrafiltration membrane were prepared through the study of membrane preparation parameters. The membranes exhibited good separation and permeation performance with good reproducibility, with a molecular weight cut-off of about 75 kDa and a permeability of about 250 L·m^-2·h^-1·bar^-1.