Fe-doped TiO2 sonocatalytic process for removal of ofloxacin and ciprofloxacin from aqueous solution

The use of antibiotics in veterinary medicine and medical applications has increased widely, and the possibility of contamination of water sources with such compounds has increased, which causes adverse effects such as increased bacterial resistance and gastrointestinal disorders in humans and other organisms. In this study, Fe-doped TiO2 nanoparticles were synthesized by the simple sol-gel method. Then, the sonocatalytic efficiency of these synthesized nanoparticles in the removal of the ofloxacin and ciprofloxacin was investigated. Scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), X-ray diffraction (XRD), and diffuse reflectance spectroscopy (DRS) analyses were used to characterize the nanoparticles. The effect of different independent parameters including pH (3–11), initial concentration of ofloxacin and ciprofloxacin (50–200 mg/L), and nanoparticle concentrations (200–700 mg/L) at different times (15–60 min) were examined for sono-catalytic removal of ofloxacin and ciprofloxacin. The results showed that the synthesized nanoparticles are very small and have a size in the range of nanometers. EDX showed the presence of Ti, Fe, and O elements in the structure of synthesized nanoparticles. The peaks of 25.68, 37.75, 48.28, 54.27, and 55.24, which are marked inside the figure of XRD, confirm the crystal structure of the anatase phase. Doping iron in the structure of titanium dioxide causes the absorption wavelength to shift to higher wavelengths and get closer to the visible region. The maximum removal efficiency and the highest constant rate of reaction for ofloxacin and ciprofloxacin at the initial concentration of 50 mg/L, the nanoparticles dosages of 700 mg/L at the reaction time of 60 min, and ultra-sound frequency of 35 kHz were obtained at pH values of 3 and 9, respectively. In this study, the degradation mechanism of the process and stability of synthesized nanoparticles were also investigated. The results showed that the nanoparticles have good stability and the use of the sonocatalytic process is an effective method to remove ofloxacin and ciprofloxacin from aqueous solutions.