Interfacial C─S Covalent Bonds Improving the Piezophotocatalytic Performance of 2D/2D g-C3N4/MoS2/PVDF Membrane for Tetracycline Degradation

Abstract

The accumulation of antibiotic pollutants in aquatic environments poses threats to ecosystems. Photocatalysis is a promising approach for removing these pollutants, but conventional powder photocatalysts often suffer from difficult recovery and poor stability. Therefore, developing efficient, stable, and easily recoverable catalytic materials is important. In this study, 2D g-C₃N₄ and MoS₂ were immobilized in a polyvinylidene fluoride (PVDF) membrane to prepare a g-C₃N₄/MoS₂/PVDF piezo-photocatalytic composite membrane. Under the combined action of visible light and mechanical vibration, the membrane achieved a TC degradation efficiency of 76.54%, indicating a synergistic enhancement between piezoelectric polarization and photocatalysis. The formation of C─S bonds at the g-C₃N₄/MoS₂ interface enhanced electronic coupling between the two phases, promoting directional migration and spatial separation of photogenerated carriers. Meanwhile, the piezoelectric built-in electric field generated by PVDF under ultrasonic excitation further suppressed carrier recombination and accelerated interfacial charge transfer. Overall, the g-C₃N₄/MoS₂/PVDF membrane shows good visible-light response, piezoelectric-assisted charge separation, mass transfer, recyclability, and stability, offering a new approach for antibiotic wastewater treatment and related membrane material design.