Removal of the hormones dexamethasone (DXM) by Ag doped on TiO2 photocatalysis

In this study, Ag/TiO2 synthetic photocatalysis is investigated as an advanced oxidation technology for degradation of Dexamethasone (DXM) in aqueous matrix. In addition, properties and activities of Ag/TiO2 and pure TiO2 were compared. Morphology and microstructures of the nanophotocatalysts were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and UV-vis diffuse reflectance spectroscopy (DRS). Results show that nanoparticles in both samples were found to be almost spherical in shape with a slight agglomeration. The coated silver has a significant effect on titanium dioxide crystallinity but not on its structure. Also Ag/TiO2 samples have highly reactive under visible light irradiation. The main aim of this study is to investigate effect of operating conditions on reaction kinetic and degradation efficiency of DXM. The UV and visible-light irradiation photocatalyst experiments were carried out with using different concentration ranges of Ag/TiO2 photocatalyst (0.75-2.5 g L−1), initial DXM (5-30 mg L−1) and H2O2 (10-20 mg L−1). The effects of pH value (3-11) and temperature (30-80) were also investigated. An optimal DXM degradation was attained at a photocatalyst concentration of 1.5 g L−1, 35 °C and pH = 3, initial DXM concentration 5 mg L−1, that resulted in the degradation efficiency for UV and VIS light irradiation 77.6% and 63.8%, respectively. In addition, by adding (15 mg L−1) H2O2 to optimal dosage, the degradation efficiency for UV and visible irradiation increased to 82.3% and 71.5%, respectively.