Insight assessment of the morphological and photocatalytic properties of ZnO-anchored graphitic carbon nitride interlayer composite for emerging antibiotic removals in water under visible light

In this study, the effect of different zinc oxide (ZnO) compositions anchored on graphitic carbon nitride (CN) was investigated through characterization and the photocatalytic degradation performance on the antibiotics tetracycline, ciprofloxacin, cephalexin, and erythromycin A. The ZnO was prepared through the phyto-synthesis route using Garcinia mangostana pericarp extract; whilst the CN was fabricated using melamine, an organic and cheap carbon nitride source. For the ZnO-anchored CN (ZnO@CN), the composition of 15% of ZnO exhibited an adequate balance of each component effect and was determined to be superior in properties. The high-resolution transmission electron microscopy images revealed the intercalation of the nanoparticles between the sheets, greatly infusing the photocatalytic and electrochemical properties. The bandgap modification of the material showed that the overall bandgap was reduced to 2.42 eV, suitable for operating in the visible region and creating multiple free radicals. For the photocatalytic deterioration of tetracycline, the optimal conditions of 15 mg of the superior material, 50 mL of the 10-ppm concentration, and 120 min of irradiation were affirmed, which removed over 95% of the antibiotic. Further investigation into other types of antibiotics reveals the efficiency was all higher than 50%. Through the mechanism proposal, the degradation pathways were elucidated regarding the molecular structure of the antibiotic.

Automated summary

This study investigated the photocatalytic degradation performance of different compositions of zinc oxide anchored on graphitic carbon nitride on antibiotics. The results showed that 15% ZnO composition exhibited superior properties. High-resolution transmission electron microscopy revealed the intercalation of nanoparticles between the sheets, greatly enhancing the photocatalytic and electrochemical properties. The optimal conditions for the photocatalytic degradation of tetracycline were determined to be 15 mg of the superior material, 50 mL of the 10-ppm concentration, and 120 min of irradiation, which removed over 95% of the antibiotic.