Removal of Co2+ ions from aqueous solution by ferrite process

A mathematical model was developed to investigate the characteristics of Co2+ removal by the pre-formed ferrite process. In this study, surface adsorption, hydrolysis-precipitation, and ion exchange were considered as Co2+ removal mechanisms, and incorporated into the model. In addition, a series of batch experiments was performed to remove Co2+ ions from aqueous solution, and the removal characteristics of Co2+ were analyzed by considering equilibrium pH,shaking time, ionic strength, and the effect of EDTA and Ca2+ as a chelating agent and a competing cation, respectively. Finally, the model proposed in this study was applied to the given experimental system, and it turned out that the pH-edge could be successfully predicted by the model. The experimental results were well-fitted by a Freundlich isotherm, and the standard enthalpy change of the reaction was 25.02 kJ . mol(-1). The removal efficiency was slightly diminished by increasing the ionic strength and the initial concentration of Co2+; however, the effect of the competing cation, Ca2+, was negligible.