Adsorption-enhanced sonophotocatalytic removal of tetracycline from water using ceria-zirconia (x)CeO2-(1-x)ZrO2 binary oxide nanocatalyst

Abstract

Objectives Tetracycline (TC) antibiotics have a risk of causing gastrointestinal and hepatic disorders and, in rare cases, photosensitivity and deposition in bone tissue. Methods Therefore, it is urgent to develop a technology that can completely remove TC remaining in the water. In this study, a new type of sonophotocatalytic decomposition system that can efficiently decompose TC, a water-based recalcitrant trace pollutant, was proposed. Results and Discussion As a sonophotocatalyst, xCeO2-(1-x)ZrO2 (x = 0, 0.25, 0.5, 0.75, and 1) binary nanocomposites were synthesized by hydrothermal methods, followed by X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscope, UV-Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area techniques. Interestingly, the 0.75CeO2-0.25ZrO2 (CZ0.75) nanocomposite had low adsorption and removal ability of TC in the absence of light, but due to the synergistic effect of the material and the advanced treatment system, the remaining TC was removed by 89.2% under sonophoto irradiation for 60 min. For CZ0.75, the effect of operating factors such as initial pH of solution, catalyst dosage, reaction time, initial TC concentration, and ultrasonic intensity was studied and the mechanism was analyzed. Conclusion In addition, through LC-MS analysis, intermediate products obtained in the TC degradation process using the CZ0.75 catalyst and the TC degradation pathway were identified.

Keywords

• tetracycline
• ceria
• zirconia
• ultrasound
• visible-light