Equilibrium and Kinetic Studies of the Adsorption of Zn(II) Ions onto Natural and Activated Kaolinites

The removal of Zn(II) ions from aqueous solution was studied using natural, thermally-activated and acid-activated kaolinite samples at different temperatures. The linear Langmuir, Freundlich and Dubinin– Radushkevich (D–R) adsorption equations were applied to describe the equilibrium isotherms. The...

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Main Authors: Ali Riza Kul, Necla Caliskan
Format: Article
Language:English
Published: SAGE Publishing 2009-02-01
Series:Adsorption Science & Technology
Online Access:https://doi.org/10.1260/026361709788921632
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author Ali Riza Kul
Necla Caliskan
author_facet Ali Riza Kul
Necla Caliskan
author_sort Ali Riza Kul
collection DOAJ
description The removal of Zn(II) ions from aqueous solution was studied using natural, thermally-activated and acid-activated kaolinite samples at different temperatures. The linear Langmuir, Freundlich and Dubinin– Radushkevich (D–R) adsorption equations were applied to describe the equilibrium isotherms. The Langmuir constants for natural kaolinite were found to be negative whereas, for the other samples, the isotherm models gave a good fit. In addition, the pseudo-first-order and pseudo-second-order 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 (ΔH 0 ), Gibbs' free energy (ΔG 0 ) and entropy (ΔS 0 ) were calculated for natural, thermally-activated and acid-activated kaolinite. These values showed that the adsorption of Zn(II) ions onto activated kaolinite was controlled by a physical mechanism and occurred spontaneously. The process of adsorption was favoured at high temperatures, with the adsorption capacity of the acid-activated kaolinite being greater relative to that of natural and thermally-activated kaolinite at various temperatures.
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spelling doaj-art-0b9e9791a3bd4532a9827f18e5186a5c2025-02-03T10:08:01ZengSAGE PublishingAdsorption Science & Technology0263-61742048-40382009-02-012710.1260/026361709788921632Equilibrium and Kinetic Studies of the Adsorption of Zn(II) Ions onto Natural and Activated KaolinitesAli Riza KulNecla CaliskanThe removal of Zn(II) ions from aqueous solution was studied using natural, thermally-activated and acid-activated kaolinite samples at different temperatures. The linear Langmuir, Freundlich and Dubinin– Radushkevich (D–R) adsorption equations were applied to describe the equilibrium isotherms. The Langmuir constants for natural kaolinite were found to be negative whereas, for the other samples, the isotherm models gave a good fit. In addition, the pseudo-first-order and pseudo-second-order 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 (ΔH 0 ), Gibbs' free energy (ΔG 0 ) and entropy (ΔS 0 ) were calculated for natural, thermally-activated and acid-activated kaolinite. These values showed that the adsorption of Zn(II) ions onto activated kaolinite was controlled by a physical mechanism and occurred spontaneously. The process of adsorption was favoured at high temperatures, with the adsorption capacity of the acid-activated kaolinite being greater relative to that of natural and thermally-activated kaolinite at various temperatures.https://doi.org/10.1260/026361709788921632
spellingShingle Ali Riza Kul
Necla Caliskan
Equilibrium and Kinetic Studies of the Adsorption of Zn(II) Ions onto Natural and Activated Kaolinites
Adsorption Science & Technology
title Equilibrium and Kinetic Studies of the Adsorption of Zn(II) Ions onto Natural and Activated Kaolinites
title_full Equilibrium and Kinetic Studies of the Adsorption of Zn(II) Ions onto Natural and Activated Kaolinites
title_fullStr Equilibrium and Kinetic Studies of the Adsorption of Zn(II) Ions onto Natural and Activated Kaolinites
title_full_unstemmed Equilibrium and Kinetic Studies of the Adsorption of Zn(II) Ions onto Natural and Activated Kaolinites
title_short Equilibrium and Kinetic Studies of the Adsorption of Zn(II) Ions onto Natural and Activated Kaolinites
title_sort equilibrium and kinetic studies of the adsorption of zn ii ions onto natural and activated kaolinites
url https://doi.org/10.1260/026361709788921632
work_keys_str_mv AT alirizakul equilibriumandkineticstudiesoftheadsorptionofzniiionsontonaturalandactivatedkaolinites
AT neclacaliskan equilibriumandkineticstudiesoftheadsorptionofzniiionsontonaturalandactivatedkaolinites