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

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

Journal of hazardous materials (2011-07-19)
Necla Caliskan, Ali Riza Kul, Salih Alkan, Eda Gokirmak Sogut, Ihsan Alacabey
ABSTRACT

The removal of Zn(II) ions from aqueous solution was studied using natural and MnO(2) 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 (ΔH(0)), Gibbs' free energy (ΔG(0)) and entropy (ΔS(0)) were calculated for natural and MnO(2) modified diatomite. These values showed that the adsorption of Zn(II) ions onto diatomite samples was controlled by a physical mechanism and occurred spontaneously.

MATERIALS
Product Number
Brand
Product Description

Supelco
Celatom®, acid-washed, for use in Total Dietary Fiber Assay, TDF-100A
Sigma-Aldrich
Hyflo® Super Cel®, filter aid, flux calcined, treated with sodium carbonate
Sigma-Aldrich
Diatomaceous earth
Sigma-Aldrich
Filter agent, Celite® 545
Sigma-Aldrich
Celite® 545, filter aid, treated with sodium carbonate, flux calcined