Adsorption of Cu2+ and Pb2+ ion on dolomite powder

Natural Turkish dolomite was shown to be effective for removing Cu2+ and Pb2+ from aqueous solution. Selected information on pH, dose required, initial metal concentration, adsorption capacity of the raw dolomite powder was evaluated for its efficiency in adsorbing metal ions. Dolomite exhibited good Cu2+ and Pb2+ removal levels at all initial metal amount tested (0.04-0.32 mmol, 20 mL). It is important to note that the adsorption capacities of the materials in equilibrium vary, depending on the characteristics of the individual adsorbent, the initial concentration of the adsorbate and pH of the solution. One hour was enough for the removal of metal ions from (0.2 mmol in 20 mL) aqueous solution. Effective removal of metal ions was demonstrated at pH values of 5.0. The adsorptive behavior of dolomite was described by fitting data generated from the study of the Langmuir and Freundlich isotherm models. The adsorption capacity of dolomite was found as 8.26 mg for Cu2+ and 21.74 mg for Pb2+, respectively, from the calculation of adsorption isotherm equation. More than 85% of studied cations were removed by dolomite from aqueous solution in single step. The mechanism for cations removal by dolomite includes surface complexation and ion exchange. (C) 2009 Elsevier B.V. All rights reserved.