The Thermodynamic and Kinetics Study of Removal of Cd(II) by Nanoparticles of Cobalt Oxide in Aqueous Solution

Cadmium is an extremely toxic metal, which even in low levels is harmful to the human body, animals and also plants. Human manufactures such as cadmium-nickel batteries and pesticides, plastic, make the earth polluted with cadmium; therefore removal of the cadmium Water is vital for human and animal. Scientists use different methods for cadmium removal including adsorption, precipitation, ion exchange, and solvent extraction. In this study the removal of cadmium ion from aqueous solution by nanoparticles of cobalt oxide were investigated. The sol-gel method was used to synthesize cobalt oxide nanoparticles. The characterization of synthesized cobalt oxide was investigated by Fourier Transfer Infrared Spectrometry (FT-IR), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM), and a Transmission Electron Microscope (TEM). The important parameters influencing on the adsorption process were studied, including pH, buffer volume, amount of adsorption, contact time, in-time differentiate temperature and Taguchi designed experiment. The kinetic of removal process was investigated and found that it is followed pseudo-second-order kinetics. In this study, four famous isotherms were considered to investigate and the results indicated that the Langmuir model gave a better fit to the experimental data.