title: Heavy metal adsorption by modified oak sawdust: thermodynamics and kinetics.
abstract: 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 100mgL(-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.
authors.affiliation: Department of Environmental Engineering, Engineering and Architecture Faculty, Selçuk University, 42031 Selçuklu-Konya, Turkey. argun@selcuk.edu.tr
authors.forename: Mehmet Emin
authors.initials: ME
authors.lastname: Argun
authors.forename: Sukru
authors.initials: S
authors.lastname: Dursun
authors.forename: Celalettin
authors.initials: C
authors.lastname: Ozdemir
authors.forename: Mustafa
authors.initials: M
authors.lastname: Karatas
mesh_terms: D000327:Adsorption; D002857:Chromium / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D006851:Hydrochloric Acid; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D019216:Metals, Heavy / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry; D010100:Oxygen / Q000378:metabolism; D029963:Quercus / Q000737:chemistry*; D013816:Thermodynamics; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods; D014873:Water Pollutants / Q000737:chemistry*; D014934:Wood / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D014873:Water Pollutants; D002857:Chromium; D003300:Copper; D009532:Nickel; D006851:Hydrochloric Acid; D010100:Oxygen