Photocatalytic activity of Gd₂O₂CO₃·ZnO·CuO nanocomposite used for the degradation of phenanthrene

Multimetal oxides nanocomposite photocatalysts based on Gd₂O₂CO₃·ZnO·CuO were prepared by a co-precipitation method and carefully characterized using a range of analytical techniques. More specifically, analysis by X-ray diffraction and electron microscopies confirmed the identity and quality of the as-synthesized powders. The photocatalytic degradation activities of these nanocomposites towards phenanthrene were then investigated by measuring the effects of catalyst dosage, irradiation time, and oxidant addition. In addition, the pseudo first-order kinetic model was used to determine the rate constant of the degradation reaction. Optimum dosages of 0.6, 0.6, and 0.4 gL⁻¹ were recorded when using CuO, Cu–CuO/ZnO, and Gd₂O₂CO₃·ZnO·CuO, respectively. In addition, the Gd₂O₂CO₃·ZnO·CuO composite exhibited a higher removal efficiency than both Cu–CuO/ZnO and the pure CuO nanoparticles. Furthermore, the addition of oxidants influenced the removal of phenanthrene from solution. Finally, the photocatalytic degradation data followed pseudo first-order kinetics as defined by the Langmuir–Hinshelwood model, which allowed prediction of the faster degradation rate by the Gd₂O₂CO₃·ZnO·CuO nanocomposite. The newly synthesized nanocomposite could therefore be considered for the removal of phenanthrene and related polycyclic aromatic hydrocarbons from contaminated water.