Abstract

Extensive studies have been conducted on advanced oxidation processes (AOPs) for the removal of antibiotics in water environments. However, the separation and recovery of powdered catalysts from water at the end of the reaction remains a great challenge, which hinders the large-scale application of powder photocatalysts. Inspired by the high sustainability, energy efficiency, and cleanliness of photocatalytic technique in antibiotic degradation, we have developed a stable and efficient ultra-thin porous g-C₃N₄/β-phase polyvinylidene fluoride (CA-CNS/β-PVDF) membrane for antibiotics removal. Under the optimal reaction conditions, the tetracycline (TC) removal rate of the membrane reached 93.12?% within 2?h due to the synergistic effect of the embedded ultra-thin porous g-C₃N₄ and β-phase polyvinylidene fluoride (PVDF). The CA-CNS/β-PVDF membrane still maintained excellent photocatalytic performance after five cycles, showing good stability and reusability. The electron paramagnetic resonance (EPR) and free radical quenching analyses suggest that the TC degradation efficiency is enhanced by the synergistic effect of free radical-non-free radical mixed pathways (?O₂, ?OH, h⁺, ¹O₂) and ¹O₂ plays an important role in the degradation process. The excellent photocatalytic antibiotics degradation performances of CA-CNS/β-PVDF membrane were still obtained in actual water samples under natural sunlight, suggesting its great application potentials. The photocatalytic mechanism, possible degradation intermediates, and degradation pathways are elucidated based on the theoretical calculations and experiments. The toxicity analysis by QSAR shows that the CA-CNS/β-PVDF membrane successfully reduces the biological toxicity of three antibiotics (TC, OTC, CIP) during the photocatalysis. In all, our work provides a universal immobilization technique of powdered photocatalysts to improve their wastewater purification efficiencies.