Enhanced adsorptive removal of methylene blue using ternary nanometal oxides in an aqueous solution

This study aims to quickly and easily produce three ternary nanometal oxides for the adsorption of methylene blue from an aqueous solution. Trimetallic oxides were synthesized using the Al-Fe binary metal oxide and precursors of copper, cobalt, and nickel. The metal oxides were investigated using the following techniques: X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and inductively coupled plasma-optical emission spectrometry (ICP-OES). XRD analysis effectively demonstrated well-dispersed nanoparticles with diameters under 20 nm. Compared to other samples, Ni-Al-Fe metal oxide samples have smaller crystal sizes and greater surface areas (239 m(2)/g). The nanometal oxides showed porous structure with pore volume of 0.08-0.15 cm(3)/g and pore diameter of 6-15 nm. The pH of the zero point of charge ( pHzpc) of 7.70, 7.34, and 7.70 were found for nanometal oxides. The adsorption capacity of adsorbents is determined by the order in which they adsorb metal precursors: Ni > Co > Cu. The efficacy of removing methylene blue increased with higher adsorption temperatures (between 27 and 57 degrees C), solution pH, initial dye concentration, nanometal oxide dosage, and contact duration. The adsorption equilibrium data were found to be in good agreement with the Langmuir model compared to the Freundlich model. The maximum adsorption capacities for Ni-Al-Fe, Co-Al-Fe, and Cu-Al-Fe were found to be 161, 94, and 19 mg/g, respectively. The pseudo-second-order kinetic model well predicted the kinetic behavior of methylene blue adsorption on metal oxides.