Adsorption of nickel(II) and cobalt(II) ions and application of surface complex formation model to ion exchange equilibria

Abstract

Process effluents containing Co2+ and Ni2+ are often encountered in chemical process industries. Their major sources are hydrometallurgy, surface treatment, and galvanizing industries, as well as wastes from the production of batteries and sludge/wastes/scrap/dust of spent catalysts. Release of large quantities of these heavy metals into the natural environment has resulted in a number of environmental problems. Therefore, removal of these metals with some cation exchange separation has been investigated. Investigations were carried out using the strongly acidic cation exchange resins Amberlite IR 120, Amberjet 1200, Amberlite 200, and Amberlite 252 ZU. Experiments focused on the measurement of exchange equilibria of Co2+ and Ni2+ for H+. Since the state of equilibrium is mainly dominated by the pH of the liquid phase, the initial pH value was varied in each series of samples. For evaluation of equilibrium parameters the surface complexation theory was applied and the generalized separation factors determined from the results. The experiments demonstrated that Ni2+ ions were more efficiently adsorbed than Co2+ ions by the strongly acidic ion exchange resins.