Construction of self-cleaning alumina ultrafiltration membrane on build-in ultrasonic porous barium titanate

Barium titanate (BaTiO₃) has received extensive attention due to its lead-free composition and excellent piezoelectric properties, enabling the build-in ultrasonic and anti-fouling performance in membrane separation processes. In this study, an asymmetric membrane consists of an alumina separation layer and a barium titanate carrier was successfully prepared for the first time, achieving dual anti-fouling properties through surface screening and in-situ ultrasound. By selecting appropriate barium titanate powder and optimizing the sintering temperature and polarization conditions, the trade-off effect between piezoelectricity and permeability was resolved, providing a good carrier for the asymmetric membrane. The alumina separation layer was fabricated on the barium titanate carrier by optimizing the slurry coating process and heat-treated at 950 °C to achieve sufficient integrity. The pore size of the alumina separation layer in the prepared Al₂O₃/BaTiO₃ asymmetric membrane is 24 nm, which is smaller than the 496 nm of the barium titanate carrier. Under a 20 V alternating voltage, the piezoelectric response signal is 35 mV. Additionally, the anti-fouling performance of the asymmetric membrane was evaluated through filtration experiments on a water-in-oil emulsion. When applying a 60 V alternating voltage, the membrane flux was essentially maintained at its initial value.