Micro-Nano Bubbles Induced Piezocatalysis with Barium Titanate/Polyvinylidene Fluoride Membrane: Synergistic Mechano-Optical Enhancement for Tetracycline Degradation

The pollution of antibiotics to the environment has attracted more and more attention from society. Therefore, it is necessary to develop effective and practical methods to degrade antibiotics. In this study, micronano bubbles (MNBs) were employed as mechanical stress to induce piezoelectric potential in barium titanate/polyvinylidene fluoride (BTO/PVDF) composite membranes, enhancing piezo-photocatalytic degradation of tetracycline (TC). Under the synergistic piezo-photocatalytic effects, the system achieved 93% TC removal within 1.5 h, with a quasi-first-order reaction rate constant (k) of 0.022 min−1. This value is 5.9-fold and 2-fold higher than those of standalone MNBs and BTO/PVDF systems, respectively. Finite element simulation analysis determined the influence of MNBs on the induced potential and piezoelectric field distribution in the composite membrane, indicating that the MNBs’ environment met the pressure conditions for BTO/PVDF to generate induced potential. Remarkably, changes in photocurrent and impedance data showed that MNBs not only enhanced light absorption but also reduced membrane impedance, improving carrier separation efficiency. Electron paramagnetic resonance (EPR) and free radical scavenging results showed that the contribution of hydroxyl radicals (•OH) in the degradation process was more significant. Therefore, the piezoelectric effect induced by MNBs is expected to provide a new idea for the treatment of antibiotic wastewater.