Ion-exchange equilibria of Cu(II) and Zn(II) from aqueous solutions with Chelex 100 and Amberlite IRC 748 resins

Two chelating ion exchange resins Chelex 100 and Amberlite IRC 748 (formerly, IRC 718), both which have iminodiacetic acid (IDA) function group, were used to exchange Cu(II) and Zn(II) from aqueous solutions. Batch experiments were performed using the Na-form resins by varying the initial concentration of metals (0.8-10.5 mol/m(3)), initial aqueous pH (1.0-5.0), and temperature (15-45 degrees C). It was shown that the amount of Cu(II) and Zn(II) exchanged increased with increasing the pH value and temperature. In addition, the amount of metals exchanged using IRC 748 resin was greater than Chelex 100 resin under comparable conditions. The equilibrium data were treated and compared by the conventional Langmuir adsorption isotherm and by the mass-action law that takes into account the activity corrections of the ions in the aqueous phase. The enthalpy changes for the present ion-exchange processes were also evaluated and discussed. (c) 2005 Elsevier B.V. All rights reserved.