Synthesis and characterization of Mg1-xNixAl2O4 and their photocatalytic behaviors towards Congo red under UV light irradiation

In this paper, MgAl2O4 nanoparticles were synthesized by the Sol-gel auto combustion method and were doped with different concentrations of Ni2+ (x= 0, 0.1, 0.05, and 0.03). By this method, a novel photocatalyst which had better decolorization percentages of Congo red(compared) to MgAl2O4 was produced. The MgAl2O4 samples were calcinated at 1000 degrees C. The samples obtained were characterized by X-ray diffraction (XRD), SEM, FT-IR, EDX, and ICP-AES. The photocatalytic activity of MgAl2O4 samples were evaluated by UV-Vis spectroscopy and diffuse reflectance spectra (DRS) to confirm the performance rate of the photocatalyst. Also, the photocatalytic properties were investigated in the presence of UV light, certain amounts of photocatalysts, and Congo red dye. The best- obtained results of the photocatalytic activity among the prepared samples were Mg0.9Ni0.1Al2O4 because this photocatalyst had a removal conversion of 99.3 % of the dye after 90 min, which was better than other photocatalysts in similar conditions. Mg0.9Ni0.1Al2O4 was used as a photocatalyst five successfully times without any changes or loss of its high photocatalytic activity for this process. In this project, we used Ni2+ to dope MgAl2O4 nanoparticles. The results decolorization percentages of Congo red showed that Mg0.9Ni0.1Al2O4 had better efficiency compared to MgAl2O4, (and other) photocatalysts.