Photocatalytic degradation of different antibiotics using TiO2–carbon composites: a case study of tetracycline and ciprofloxacin

Abstract

With the in-depth study of photocatalytic degradation of antibiotics, it can be learned that photocatalysts show different performances when degrading different antibiotics. In this work, an efficient photocatalytic material was synthesized using TiO₂ and bagasse, and its characteristics were verified by SEM, EDS, TEM, FT-IR spectroscopy, XRD, I–t, EIS, M-S, and UV-vis DRS. Tetracycline and ciprofloxacin were used as target contaminants to explore the degradation performance and degradation mechanism of catalysts for antibiotics with different properties. The experiments showed that the applicable pH range for ciprofloxacin was narrower and tetracycline required a higher dosage for effective degradation. The ESR and capture experiments showed that there were several reactive groups produced in the degradation system. Overall, the reactive species that played a major role in the degradation of tetracycline and ciprofloxacin were h⁺, ¹O₂, and h⁺, respectively. Furthermore, it can also be seen that under acidic or alkaline conditions, the direct contact oxidation dominated by h⁺ was weakened and the role of reactive species such as ˙OH, ˙O₂⁻ and e⁻ in TC degradation and ˙OH, ˙O₂⁻ and ¹O₂ in CIP degradation was strengthened, respectively. It is clear from the liquid mass that both the reactive groups and the pH of the solution impacted the production and elimination of intermediates. This work highlights the variability of the photocatalyst in degrading different pollutants, suggesting the need for more targeted preparation of photocatalysts.