Piezocatalytic PVDF nanofibrous membrane embedded Mn-doped bismuth sodium titanate for continuous-flow peroxymonosulfate activation and tetracycline degradation

Piezocatalysis holds great potential for advanced oxidation processes (AOPs), yet the practical application of conventional powder catalysts is severely hindered by their poor recoverability and reusability. To overcome the limitation, a polyvinylidene fluoride (PVDF)-based piezocatalytic nanofibrous membrane embedded with manganese-doped bismuth sodium titanate (BNMT) was fabricated via electrospinning, with polyethylene glycol (PEG) incorporated as a hydrophilicity enhancer under sonication. Under ultrasound-assisted peroxymonosulfate (PMS) activation in a continuous-flow system, the optimized membrane (0.3B-PEG-PVDF) achieved 90.7 % degradation of tetracycline hydrochloride (TC, 10 mg/L) within 60 min. Quenching experiments and electron paramagnetic resonance spectroscopy revealed a unique mixed radical/non-radical pathway, with singlet oxygen ( 1 O 2 ) and hydroxyl radical (•OH) as the dominant reactive species. The piezocatalytic membrane maintained over 77 % TC removal after eight consecutive cycles, with negligible metal leaching and excellent anti-interference performance in real water matrices. This work provides a facile strategy for constructing efficient, recyclable piezocatalytic membranes and advances the practical application in continuous-flow wastewater treatment.