Cerium-Doped Titanium Dioxide (CeT) Hybrid Material, Characterization and Spiramycin Antibiotic Photocatalytic Activity

Recently, aquatic life and human health are seriously threatened by the release of pharmaceutical drugs. For a sustainable ecosystem, emerging contaminants like antibiotics must be removed from drinking water and wastewater. To address this issue pure and cerium-doped titanium dioxide (CeT) nanoparticles were produced with stable tetragonal (anatase) lattices by room temperature sol–gel method and employing the inorganic titanium oxysulfate (TiOSO4) as titanium precursor. The structural analysis by X-ray diffraction (XRD) revealed that at calcination temperature of 600 °C all (un and doped) powders were composed of crystalline anatase TiO2 with the crystallite sizes in the range of 13.5–11.3 nm. UV–vis DRS spectroscopy revealed that the most narrowed bandgap value of 2.75 eV was calculated for the 0.5CeT sample containing the optimum dopant content of 0.5 weight ratio. X-ray spectroscopy (XPS) confirmed the presence of the impurity level Ce3+/Ce4+, which became responsible for the decrease in bandgap as well as for the photoinduced carriers recombination rate. Photocatalytic tests showed that the maximum decomposition of the model spiramycin (SPR) antibiotic pollutant was 88.0% and 77.0%, under UV and visible light, respectively. According to the reaction kinetics, SPR decomposition adhered to the Langmuir–Hinshelwood (L–H) model and via ROS experiments mainly hydroxyl radicals (OH•) followed by photogenerated holes (h+s) become responsible for the pollutant degradation. In summary, this study elaborates on the role of xCeT nanoparticles as an efficient photocatalyst for the elimination of organic contaminants in wastewater.