Isotherm and Kinetic Studies of Pb(II) Adsorption on Raw and Modified Diatomite by Using Non-Linear Regression Method


Gökırmak Söğüt E. , Çalışkan Kılıç N.

Fresenius Environ Bull, vol.26, no.4, pp.2721-2729, 2017 (Refereed Journals of Other Institutions) identifier

  • Publication Type: Article / Article
  • Volume: 26 Issue: 4
  • Publication Date: 2017
  • Title of Journal : Fresenius Environ Bull
  • Page Numbers: pp.2721-2729
  • Keywords: Non-linear methods, diatomite, modification, kinetic, thermodynamics, GRANULAR ACTIVATED CARBON, AQUEOUS-SOLUTION, METHYLENE-BLUE, LEAD IONS, EQUILIBRIUM, SORPTION, REMOVAL, MODELS, PARAMETERS, CR(VI)

Abstract

This study presents the evaluation of the

original diatomite (DO) and manganese oxide

modified (DMn) diatomite used as adsorbents for Pb

(II) removal from aqueous solution. The

experimental data were fitted to the non-linear twoparameter equation of Langmuir, Freundlich,

Dubinin-Radushkevich, and non-linear threeparameter equation of Redlich-Peterson, Sips and

Toth Isotherms. The correlation coefficient (R2

),

standard error (S.E) and Chi-VTXDUH Ȥ2

) values were

used to select the best theoretical isotherm.

Adsorption mechanism of Pb(II) ion onto the DO was

explained by heterogeneous adsorption model while

homogenous adsorption model was used to explain

the adsorption on DMn. Also, both adsorbents were

observed to comply better with the three-parameter

isotherms. Pseudo first-order, pseudo second-order,

Elovich and intraparticle diffusion equations were

used to describe the adsorption rate of Pb(II). The

experimental data were well fitted by the pseudosecond-order kinetic model. Thermodynamic

SDUDPHWHUV VXFK DV IUHH HQHUJ\ ǻ*o

), enthalpy

ǻ+o

DQG HQWURS\ ǻ6o

) showed spontaneous and

endothermic in nature of adsorption for both of

adsorbents.