Effective degradation of tetracycline antibiotic residues in municipal and hospital effluents using light-assisted graphitic carbon nitride
摘要
Hospitals that use large quantities of antibiotics discharge significant residual amounts into the environment. Wastewater from these facilities can cause the development and spread of antibiotic-resistant bacteria and genes in the ecosystem. This study explores a sustainable approach to control antibiotic residues in municipal and hospital wastewaters using graphitic carbon nitride (g/CN) photocatalyst. The synthesized catalyst exhibited unique properties, including non-toxicity, high thermal stability, strong light adsorption, and a low band gap energy (2.7 eV). The degradation efficiencies of the target pollutant tetracycline (TC/A), using g/CN were 83.5%, 86.4%, 92.3%, and 97.8% at pH 4.0, 6.0, 8.0, and 10.0, respectively. Under solar light, g/CN almost completely oxidized TC/A at concentrations of 0.1–0.5 mg L⁻1, suggesting its potential for wastewater treatment. Besides, as the initial concentration increased from 0.1 to 5 mg L⁻1, the time required to decompose 50% of TC/A also increased from 23.18 to 41.75 min, respectively. The synthesized photocatalyst exhibited high reusability, with the TC/A degradation rate remaining above 80% after six cycles. The reduction of total organic carbon and formation of by-products demonstrate that g/CN transforms and mineralizes TC/A into non-toxic inorganic compounds. g/CN also displays high TC/A removal efficiencies (> 98.8%) in municipal and hospital wastewater, confirming its practical value. Therefore, it could be a promising candidate for reducing antibiotic pollutants and minimizing their potential risks to environmental and human health.