Black binary nickel cobalt oxide nano-powder prepared by cathodic electrodeposition; characterization and its efficient application on removing the Remazol Red textile dye from aqueous solution

Abstract

In this current research, black binary Ni–Co oxide nano-powder was synthesized by cathodic electrodeposition followed by calcination at 700 °C for 1 h. The electrodeposition was carried out from Watts bath contains NO3− ions. The impact of the operating deposition conditions, such as current density, temperature, pH and NO3− ion concentrations, on electrodeposition process were examined. The XRD patterns show that the powder oxide consists mainly of NiCo2O4 phase in addition to small amount of NiO phase. The particle size of the obtained powder investigated by transmission electron microscopy (TEM) revealed an average value of 22.9 nm. The nano-powder was tested for the effective elimination of Remazol Red textile dye from aqueous solution. The influences of exposure time, initial dye concentrations, temperature and initial pH on the elimination efficiency were studied too. The adsorption kinetics was best fitted to the pseudo-first -order kinetic model and the Langmuir isotherm was applicable to describe the adsorption process showing maximum monolayer adsorption capacity of 45.25 mg/g. Thermodynamic parameters indicated that the adsorption process was endothermic and spontaneous. The characterization features of the powder were investigated by XRD, energy dispersive X-ray (EDX), scanning electron microscope (SEM) and TEM.