Charge transfer complexation between some transition metal ions with azo Schiff base donor as a smart precursor for synthesis of nano oxides: An adsorption efficiency for treatment of Congo red dye in wastewater

Abstract

This mentioned article aimed to synthesized of nanostructured CuO, Co3O4 and NiO oxides based on the thermal decomposition of precursors associated from the complexation between azo Schiff base chelate (2,2′-((1E,1′E)-hydrazine-1,2-diylidenebis(methaneylylidene))bis(4-((E)-phenyldiazenyl)phenol) (NNOO)) and metal chloride salts with 1:1 M ratio. The NNOO azo Schiff base chelate, and its Cu(II), Co(II) and Ni(II) complexes were synthesized and discussed using microanalytical, molar conductance, magnetic properties, FT-IR, UV–Vis, 1H NMR, mass, and TGA (thermogravimetric analysis) techniques. According to the microanalysis and spectroscopic results, the coordination mode between azo Schiff base ligand and the central metal ion was occurs through NNOO donating atoms of azo Schiff base ligand. The electronic spectra and magnetic susceptibility analyses concluded that all synthesized metal complexes have an octahedral geometrical structural. The metal oxides (CuO, Co3O4, and NiO) nanoparticles were synthesized after the calcination of azo Schiff base complexes at 800 °C in a static air. The assignments of CuO, Co3O4 and NiO nanostructured oxides were discussed based on the FTIR, XRD, and TEM analysis technique. The ability of CuO, Co3O4 and NiO was compared by catalytic degradation of Congo red azo dye. The decolorization behavioral of Congo red dye was examined using spectroscopic UV–Vis techniques. Furthermore, the rate of catalytic decolorization activity of Congo red dye using prepared metal oxides was successfully performed. The dye has been successfully decolorized by ~57% in the presence of Co3O4 NPs at room temperature.