Adsorption of Zinc(II) on diatomite and manganese-oxide-modified diatomite: A kinetic and equilibrium study


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Caliskan N. , Kul A. R. , Alkan S., Sogut E. G. , Alacabey I.

JOURNAL OF HAZARDOUS MATERIALS, cilt.193, ss.27-36, 2011 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 193
  • Basım Tarihi: 2011
  • Doi Numarası: 10.1016/j.jhazmat.2011.06.058
  • Dergi Adı: JOURNAL OF HAZARDOUS MATERIALS
  • Sayfa Sayıları: ss.27-36

Özet

The removal of Zn(II) ions from aqueous solution was studied using natural and MnO2 modified diatomite samples at different temperatures. The linear Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption equations were applied to describe the equilibrium isotherms. From the D-R model, the mean adsorption energy was calculated as >8 kJ mol(-1), indicating that the adsorption of Zn(II) onto diatomite and Mn-diatomite was physically carried out. In addition, the pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to determine the kinetic data. The experimental data were well fitted by the pseudo-second-order kinetic model. Thermodynamic parameters such as the enthalpy (Delta H-0), Gibbs' free energy (Delta G(0)) and entropy (Delta S-0) were calculated for natural and MnO2 modified diatomite. These values showed that the adsorption of Zn(II) ions onto diatomite samples was controlled by a physical mechanism and occurred spontaneously. (C) 2011 Elsevier B.V. All rights reserved.