Abstract
A comparative study on the adsorption of zinc(II) and cobalt(II) from aqueous solutions onto Indion BSR, an indigenous cation-exchange resin, was undertaken in the present work. Various parameters for the removal of Co(II) and Zn(II) such as the initial solution pH, contact time, resin and metal ion concentration were optimized. The equilibrium data obtained were well fitted by both the Langmuir adsorption isotherm at pH 6.0 for 500 mg resin and the Freundlich adsorption isotherm under optimum conditions of contact time and pH 5.0 for 250 mg resin at 30°C. The adsorption of Zn(II) and Co(II) on this cation-exchange resin followed first-order reaction kinetics. Film diffusion of Co(II) and Zn(II) in this ion-exchange resin was shown to be the main rate-limiting step over the concentration range studied. The studies showed that the resin could be used as an efficient adsorbent for the removal of Co(II) and Zn(II) from aqueous solutions.