Photocatalytic degradation of antibiotic ciprofloxacin using TiO2:Ag nanograins

Abstract

The effective degradation of antibiotics like ciprofloxacin (CPF) has become a critical global concern due to their environmental persistence and associated health risks. This study presents the highly efficient photocatalytic activity of hydrothermally synthesized metal-doped TiO2 nanograins for the CPF degradation under natural solar light irradiation (∼830 W/m2). Electron microscopy confirmed that all samples consisted of uniformly distributed spherical nanograins, forming well-defined surface microstructures. Among the synthesized metal-doped TiO2 samples, Ag-doped TiO2 (TiO2:Ag) exhibited the highest photocatalytic CPF degradation efficiency, attributed to the coexistence of both Ag+ and Ag0 species. The incorporation of Ag+ dopants reduced the optical bandgap energy of TiO2:Ag, thereby enhancing light absorption across a broader spectral range. Furthermore, the dopant energy levels introduced by Ag+, along with the plasmonically active Ag0 neutral atoms, suppressed photocarrier recombination and promoted efficient charge separation. As a result, the TiO2:Ag nanograins achieved a photocatalytic CPF degradation efficiency of up to 99.25 % within a relatively short reaction time of 120 min. These findings suggest that hydrothermally synthesized spherical TiO2:Ag nanograins hold significant potential for application in membrane technologies aimed at the effective degradation of antibiotic contaminants such as CPF. © 2025 Elsevier Ltd and Techna Group S.r.l.