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Heavy metal adsorption by modified oak sawdust: Thermodynamics and kinetics
Ist Teil von
Journal of hazardous materials, 2007-03, Vol.141 (1), p.77-85
Ort / Verlag
Amsterdam: Elsevier B.V
Erscheinungsjahr
2007
Link zum Volltext
Quelle
Access via ScienceDirect (Elsevier)
Beschreibungen/Notizen
This paper describes the adsorption of heavy metal ions from aqueous solutions by oak (
Quercus coccifera) sawdust modified by means of HCl treatment. Our study tested the removal of three heavy metals: Cu, Ni, and Cr. The optimum shaking speed, adsorbent mass, contact time, and pH were determined, and adsorption isotherms were obtained using concentrations of the metal ions ranging from 0.1 to 100
mg
L
−1. The adsorption process follows pseudo-second-order reaction kinetics, as well as Langmuir and D–R adsorption isotherms. The paper discusses the thermodynamic parameters of the adsorption (the Gibbs free energy, entropy, and enthalpy). Our results demonstrate that the adsorption process was spontaneous and endothermic under natural conditions. The maximum removal efficiencies were 93% for Cu(II) at pH 4, 82% for Ni(II) at pH 8, and 84% for Cr(VI) at pH 3.