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Adsorption kinetics of heavy metal ions on NaA zeolite synthesized from fly ash. |
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Abstract Single-phase zeolite NaA was synthesized from fly ash using two-stage method. The structure and performance of the products were characterized. With the static method, the adsorption properties of NaA zeolite to Cu(ΙΙ), Cr(Ⅵ) and Zn(ΙΙ) in aqueous solution was studied and adsorption mechanism was discussed from kinetic point of view. Under the experinental concentration and pH value, the equilibrium adsorption data fitted to Langmuir isotherms and the greatest adsorption capacity of Cu(ΙΙ), Cr(Ⅵ) and Zn(ΙΙ) was 82.30, 65.96 and 47.78 mg/g, respectively. The existing way and size of three heavy metal ions in aqueous solution were important influential factors on adsorption behavior. Moving Boundary Model analysis showed that the adsorption rate of Cu(ΙΙ) and Zn(ΙΙ) was mainly governed by liquid film diffusion, and intra-particle diffusion was important controlling factor for the adsorption rate of Cr(Ⅵ). The adsorption processes of three heavy metal ions followed a pseudo-second-order kinetic model.
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Received: 30 May 2008
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