One-pot synthesis of ZnO/g-C3N4 with enhanced photocatalytic activity for levofloxacin degradation and uranium extraction

This study synthesized ZnO/g-C₃N₄ heterojunctions via a facile one-pot method. Specifically, solid-state grinding of Zn(OH)₂ and melamine followed by calcination at 550 °C for 4 h enabled in situ co-growth of ZnO and g-C₃N₄. Characterization through XRD, FTIR, XPS, and SEM confirmed successful synthesis of the material by revealing its microstructure and chemical composition. TG and BET analyses further revealed enhanced active sites in the composite relative to individual components. UV-Vis DRS, EIS, and Mott-Schottky measurements validated superior optoelectronic properties of the hybrid material. Under simulated solar irradiation (55 W Xe lamp), ZC-10 (1.0 g/L) achieved 92 % degradation of levofloxacin (LVF, 10 mg/L in 100 mL solution) within 120 min, exhibiting reaction rates 2.4-fold and 3.8-fold higher than pristine ZnO and g-C₃N₄, respectively. Notably, in uranium extraction experiments (100 W Xe lamp), ZC-10 (0.20 g/L) achieved a total uranium removal mass of 398 mg/g with 99 % efficiency from 50 mL of 80 mg/L U(VI) solution after 240 min. Cycling tests confirmed the robust stability of the photocatalyst. Mechanistic investigations via EPR and targeted quenching experiments identified $·O_2^{-}$ as the primary reactive species responsible for LVF degradation. This integrated ZnO/g-C₃N₄ system demonstrates great potential for environmental engineering applications in antibiotic remediation and uranium recovery.