A Comparative Study on the Photocatalytic Degradation of Doxycycline Antibiotic in the Presence of ZnO/g-C3N4 and TiO2/g-C3N4 Composites

Abstract

     This study employed a simple hydrolysis method to synthesize two novel nanocomposites: ZnO/g-C₃N₄ (ZCN) and TiO₂/g-C₃N₄ (TCN). Characterization results confirmed the successful integration of ZnO and TiO₂ nanoparticles onto g-C₃N₄ nanosheets, resulting in enhanced optical absorption in the visible light region. Both synthesized ZCN and TCN composites exhibited higher photocatalytic degradation efficiency of the antibiotic doxycycline under visible light irradiation compared to their individual component materials. This enhancement is attributed to the formation of heterojunction between TiO₂ or ZnO and porous g-C₃N₄, which improves electron-hole pair separation and reduces recombination. The photocatalytic degradation kinetics of doxycycline using ZCN and TCN followed a pseudo-first-order model, with both catalysts demonstrating operational stability and effectiveness in antibiotic photodegradation.