Kinetics and Thermodynamics of Aqueous Copper Adsorption by Ca-Al-Zn LDH and Its Calcined Product

Document Type : Original Article

Authors

1 Analysis and Evaluation Department, Egyptian Petroleum Research Institute

2 Giza north power station, Ministry of electricity and energy, Giza, Egypt

3 Department of Mechanical Power Engineering, Benha Faculty of Engineering, Benha University, Benha, Qalubia, Egypt

4 Analysis and evaluation department Egyptian petroleum research institute

Abstract

The Ca-Al-Zn layered double hydroxide (LDH) which synthesized by co-precipitation method and its calcined product were used in removal of Cu(II) from aqueous solutions. At optimum conditions, the calcined Ca-Al-Zn LDH product has higher potential application in cupreous ions adsorption field (45.2mg/g) than the uncalcined LDH (38.8mg/g). Langmuir and Freudlich models were used to optimizing the adsorption process and pseudo-first and pseudo-second order models were used to evaluating the adsorption kinetics of Cu(II) onto Ca-Al-Zn LDH and its calcined product. Langmuir model fitted the experimental data better than Freundlich model and pseudo-first order model is more sufficient to depict the adsorption kinetics. From thermodynamic studies; Gibbs free energy (∆G°), Enthalpy change (∆H°) and Entropy change (∆S°) revealed that the adsorption processes are a spontaneous, endothermic and randomness processes at the solid-solution interface during adsorption.

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History

  • Receive Date: 30 March 2020
  • Revise Date: 09 May 2020
  • Accept Date: 04 June 2020

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