Understanding Tetracycline-Nanoceramic Interactions: A Study Using UV-Vis, Fluorescence Spectroscopy and HPLC

Tetracyclines (TCs) are among the most widely used antibiotics for disease control and livestock feed due to their broad-spectrum therapeutic properties. However, their extensive use, particularly oxytetracycline (OTC) and doxycycline (DC), has led to their widespread presence in water and soil environments, raising ecological and public health concerns. The electron-rich functional groups of TCs, including ketone, carboxyl, amino, and hydroxyl moieties, enable strong complexation with metal oxides, making nanoceramic materials promising adsorbents for their removal. In this study, the adsorption behavior of OTC and DC onto commercial nanoceramics (SiO₂, Al₂O₃, TiO₂, and ZnO) was investigated using UV-Vis absorption, fluorescence spectroscopy, and high-performance liquid chromatography (HPLC). Spectroscopic analyses revealed significant reductions in absorbance and fluorescence intensity upon nanoceramic addition, indicating strong antibiotic adsorption and fluorescence quenching, particularly for ZnO and Al₂O₃. TiO₂ also demonstrated moderate adsorption capacity, while SiO₂ exhibited a distinct behavior, enhancing fluorescence intensity and increasing HPLC peak areas, suggesting weaker adsorption interactions possibly influenced by solvation effects or surface passivation. HPLC results confirmed that DC exhibited a higher adsorption rate than OTC, with TiO₂ and Al₂O₃ achieving over 80 % removal efficiency. The unique behavior of SiO₂ suggests that it does not strongly adsorb tetracyclines but may influence their solubility or molecular stability. These findings provide mechanistic insights into tetracycline-nanoceramic interactions and underscore the importance of material-specific adsorption behaviors for wastewater treatment applications. HIGHLIGHTSThis study uses multiple instruments, including UV-Vis and fluorescence spectrophotometers, as well as high-performance liquid chromatography, to assess the effect of incorporating commercial nanoceramics into tetracycline analogs. GRAPHICAL ABSTRACT