Nanocomposites For Optical Properties and Effective Photocatalytic Degradation of Pollutants in Water

Abstract In this study, chromium (III) oxide (Cr2O3) and potassium oxide (K2O) nanoparticles (NPs) were synthesized by combustion. Mixed oxides of varying concentrations in the form of (1-x)Cr2O3/xK2O (x = 0.1, 0.3, 0.5, and 0.7) were prepared. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), and optical measurements were used to investigate the properties of these nanoparticles. XRD indicates that the grain size decreased as the K2O content increased. Additionally, HR-TEM revealed several types of shapes, such as hexagonally-shaped nanoparticles. The optical measurements showed a blue shift indicating a minor modification to the band structure during the Cr2O3/xK2O mixing. The (1-x)Cr2O3/xK2O nanoparticles were used as catalysts in wastewater during a photocatalytic process. Orange G was chosen as an impurity in the water. The absorbance curves of Orange G in the water were measured at different times in the presence of the same quantity of Cr2O3/xK2O NPs. After 120 min, the efficiency reached 13% and 38% for (1-x)Cr2O3/xK2O NPs with x = 0.1 and 0.7, respectively. The experimental results were analyzed by pseudo first- and second-order models and intra-particle diffusion models. A first-order kinetic model had the best fit for the (1-x)Cr2O3/xK2O NPs. The strongest relationship occurred with a composition of 0.1Cr2O3/0.7K2O.