Equilibrium studies on the adsorption of Co(II) and Ni(II) by modified silica gels: One-component and binary systems

Eveliina Repo; Roman Petrus; Mika Sillanpää; Jolanta K. Warchoł

doi:10.1016/j.cej.2011.06.019

Equilibrium studies on the adsorption of Co(II) and Ni(II) by modified silica gels: One-component and binary systems

Eveliina Repo, Roman Petrus, Mika Sillanpää, Jolanta K. Warchoł

Research output: Contribution to journal › Article › peer-review

44 Citations (Scopus)

Abstract

The BiLangmuir and Redlich-Peterson models as well as their extended equations were tested for the modeling of one- and two-component adsorption equilibrium of Co(II) and Ni(II) ions on EDTA- and DTPA-modified silica gel. An approach consisting in initialization of parameter values and non-linear parameter estimation by minimization of two objective functions (MPSD and ERRSQ) was proposed to assure that equilibrium parameters obtained related to the global minimum. A usage of the experimentally obtained value of maximum adsorption capacity as an initial guess made an iteration procedure well-posed and independent of the K_i guess values. None of the parameters obtained for one-component systems satisfactorily helped in prediction of the two-component adsorption equilibrium. The application of the extended BiLangmuir model identified the coexistence of low- and high-energy active sites on EDTA/DTPA-silica gel that showed an unequal ability for Co(II) and Ni(II) adsorption.

Original language	English
Pages (from-to)	376-385
Number of pages	10
Journal	Chemical Engineering Journal
Volume	172
Issue number	1
DOIs	https://doi.org/10.1016/j.cej.2011.06.019
Publication status	Published - 1 Aug 2011
Externally published	Yes

Keywords

Adsorption isotherm
Chelating agent
Modeling
One-component
Two-component

ASJC Scopus subject areas

General Chemistry
Environmental Chemistry
General Chemical Engineering
Industrial and Manufacturing Engineering

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10.1016/j.cej.2011.06.019

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title = "Equilibrium studies on the adsorption of Co(II) and Ni(II) by modified silica gels: One-component and binary systems",

abstract = "The BiLangmuir and Redlich-Peterson models as well as their extended equations were tested for the modeling of one- and two-component adsorption equilibrium of Co(II) and Ni(II) ions on EDTA- and DTPA-modified silica gel. An approach consisting in initialization of parameter values and non-linear parameter estimation by minimization of two objective functions (MPSD and ERRSQ) was proposed to assure that equilibrium parameters obtained related to the global minimum. A usage of the experimentally obtained value of maximum adsorption capacity as an initial guess made an iteration procedure well-posed and independent of the Ki guess values. None of the parameters obtained for one-component systems satisfactorily helped in prediction of the two-component adsorption equilibrium. The application of the extended BiLangmuir model identified the coexistence of low- and high-energy active sites on EDTA/DTPA-silica gel that showed an unequal ability for Co(II) and Ni(II) adsorption.",

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AU - Repo, Eveliina

AU - Petrus, Roman

AU - Sillanpää, Mika

AU - Warchoł, Jolanta K.

PY - 2011/8/1

Y1 - 2011/8/1

N2 - The BiLangmuir and Redlich-Peterson models as well as their extended equations were tested for the modeling of one- and two-component adsorption equilibrium of Co(II) and Ni(II) ions on EDTA- and DTPA-modified silica gel. An approach consisting in initialization of parameter values and non-linear parameter estimation by minimization of two objective functions (MPSD and ERRSQ) was proposed to assure that equilibrium parameters obtained related to the global minimum. A usage of the experimentally obtained value of maximum adsorption capacity as an initial guess made an iteration procedure well-posed and independent of the Ki guess values. None of the parameters obtained for one-component systems satisfactorily helped in prediction of the two-component adsorption equilibrium. The application of the extended BiLangmuir model identified the coexistence of low- and high-energy active sites on EDTA/DTPA-silica gel that showed an unequal ability for Co(II) and Ni(II) adsorption.

AB - The BiLangmuir and Redlich-Peterson models as well as their extended equations were tested for the modeling of one- and two-component adsorption equilibrium of Co(II) and Ni(II) ions on EDTA- and DTPA-modified silica gel. An approach consisting in initialization of parameter values and non-linear parameter estimation by minimization of two objective functions (MPSD and ERRSQ) was proposed to assure that equilibrium parameters obtained related to the global minimum. A usage of the experimentally obtained value of maximum adsorption capacity as an initial guess made an iteration procedure well-posed and independent of the Ki guess values. None of the parameters obtained for one-component systems satisfactorily helped in prediction of the two-component adsorption equilibrium. The application of the extended BiLangmuir model identified the coexistence of low- and high-energy active sites on EDTA/DTPA-silica gel that showed an unequal ability for Co(II) and Ni(II) adsorption.

KW - Adsorption isotherm

KW - Chelating agent

KW - Modeling

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KW - Two-component

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Equilibrium studies on the adsorption of Co(II) and Ni(II) by modified silica gels: One-component and binary systems

Abstract

Keywords

ASJC Scopus subject areas

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