Removal of copper and cobalt from aqueous solutions using natural clinoptilolite

B. B. Mamba, D. W. Nyembe, A. F. Mulaba-Bafubiandi

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26 Citations (Scopus)


Southern African clinoptilolite capability as an ion-exchanger with respect to Cu2+ and Co2+ was investigated in order to consider its possible application at removing metals from aqueous solutions. The column method was used in the cationexchange processes with synthetic solution concentrations of 0.07 M (3.86 g/l), 0.33 M (19.31 g/l) and 0.66 M (38.63 g/l) of Cu2+ solution and 0.07 M (3.34 g/l), 0.33 M (16.69 g/l) and 0.66 M (33.37 g/l) of Co2+ solution. Synthetic non-mixed sulphate solutions of copper and cobalt recorded maximum cation uptakes of 79% and 63% with 0.02 M HCl-activated clinoptilolite respectively. From the Cu/Co mixed solutions, both cobalt and copper recorded a 79% uptake with 0.02 M HCl-activation. The 0.04 M HCl activation gave percentage removals of 79% and 77% for Co2+ and Cu2+ respectively. In the ion-exchange evaluation part of the study, it was found that in every concentration range, the adsorption mass ratio of clinoptilolite to metal concentration conformed to both Langmuir and Freundlich adsorption isotherms. However, the non-mixed aqueous solutions of Cu2+ and Co2+ ftted mainly the Langmuir equation. It was found that the adsorption process depends on the hydrated radius of the cation being exchanged, the concentration of the acid that activates the clinoptilolite and the concentration of the targeted cation in solution.

Original languageEnglish
Pages (from-to)307-314
Number of pages8
JournalWater S.A.
Issue number3
Publication statusPublished - Apr 2009


  • Cation exchange
  • Clinoptilolite
  • Cobalt; wastewater
  • Copper

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Water Science and Technology
  • Waste Management and Disposal
  • Management, Monitoring, Policy and Law


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