Hydrophilic porous PVDF membrane embedded with BaTiO3 featuring controlled oxygen vacancies for piezocatalytic water cleaning

High-efficient and recyclable piezocatalysts are promising to utilize natural mechanical energy in piezocatalytic degradation for environmental purification. Herein, a new piezoelectric membrane with dual piezoelectric potentials was fabricated by embedding piezoelectric BaTiO3 nanocubes in piezoelectric PVDF polymeric film. In particular, the pre-modified controlled oxygen vacancies in BaTiO3 nanocubes (BTO-OVs) enhanced the adsorption and activation of dissolved oxygen in water, promoting the generation of reactive radicals. And the PVDF film embedded by BTO-OVs had boosted piezoelectric property and improved hydrophilicity and porosity after socking. Thus, the hydrophilic porous composite membrane (HPVDF/BTO-OVs) had efficient adsorption and piezocatalytic degradation of Bisphenol A in water under ultrasonic vibration and the removal efficiency is 14 times higher than that of pure PVDF film. In addition, the HPVDF/BTO-OVs membrane adhered on impeller can effectively remove BPA under 900 rpm stirring, which provided a promising material for water purification utilizing low-frequency mechanical energy from nature.