Removal of Pb(II) and Cu(II) Ions from ‎Aqueous Solutions by Cadmium Sulfide ‎Nanoparticles

   In this study, cadmium sulfide nanoparticles (CdS NPs) were prepared, characterized and used as a new adsorbent for simultaneous removal of Pb(II) and Cu(II) ions from aqueous solutions. Using a batch adsorption method, the effects of solution pH, contact time, adsorbent dose, and temperature were studied and optimized. Removal efficiencies, higher than 98% were obtained for both the metal ions at the optimum conditions. The adsorption process was rapid, as equilibrium was achieved within 15 min. The kinetic and isotherm experiment data could be well described with the pseudo-second order kinetic model and the Freundlich isotherm model. The maximum adsorption capacities for Pb(II) and Cu(II) ions were 200 mg/g and 166.7 mg/g, respectively. The thermodynamics of adsorption process such as changes in standard free energy, enthalpy and entropy were also discussed. This study revealed that CdS NPs are effective adsorbent for rapid removal of Pb(II) and Cu(II) ions from aqueous solutions.