Adsorption of lead(II) from aqueous solution onto Hydrilla verticillata |
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Authors: | Ling-zhi Huang Guang-ming Zeng Dan-lian Huang Li-feng Li Peng-mian Huang Chang-bin Xia |
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Affiliation: | (1) College of Environmental Science & Engineering, Hunan University, 410082 Changsha, People’s Republic of China;(2) College of Chemistry & Environmental Engineering, Changsha University of Science & Technology, 410015 Changsha, People’s Republic of China |
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Abstract: | The adsorption of Pb(II) onto Hydrilla verticillata was examined in aqueous solution with parameters of pH, adsorbent dosage, contact time and temperature. The linear Langmuir and Freundlich models were applied to describe equilibrium isotherms, and both models fitted well. The monolayer adsorption capacity of Pb(II) was found as 104.2 mg/g at pH 4 and 25°C. Dubinin–Radushkevich (D–R) isotherm model was also applied to the equilibrium data. The mean free energy of adsorption (15.81 kJ/mol) indicated that the adsorption of Pb(II) onto H. verticillata may be carried out via chemical ion-exchange mechanism. Thermodynamic parameters, free energy (ΔG 0), enthalpy (ΔH 0) and entropy (ΔS 0) of adsorption were also calculated. These parameters showed that the adsorption of Pb(II) onto H. verticillata was a feasible, spontaneous and exothermic process in nature. The influence of Cd2+, Cu2+ and Ni2+ on adsorption of Pb2+ onto H. verticillata was studied, too. In the investigated range of operating conditions, it was found that the existence of Cd 2+, Cu 2+ and Ni 2+ had no impact on the adsorption of Pb2+. |
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Keywords: | Pb(II) Hydrilla verticillata Adsorption isotherm Thermodynamics |
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