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

Abstract

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 redcompared to MgAl₂O₄ was produced. The MgAl₂O₄ samples were calcinated at 1000 ⁰C. 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 reddye. The best- obtained results of the photocatalytic activity among the prepared samples were Mg_0.9Ni_0.1Al₂O₄ 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. Mg_0.9Ni_0.1Al₂O₄ 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 redshowed that Mg_0.9Ni_0.1Al₂O₄ hadbetter efficiency compared to MgAl₂O_4, and other photocatalysts.