Ion exchange studies on natural and modified zeolites and the concept of exchange site accessibility

Vassilis J. Inglezakis, Maria M. Loizidou, Helen P. Grigoropoulou

Research output: Contribution to journalArticle

114 Citations (Scopus)


In the present study natural and Na-rich form of clinoptilolite are examined, in respect to ion exchange of Pb2+, Cu2+, Cr3+, and Fe3+. Equilibrium and kinetic studies performed, under the same normality (0.01 N). Equilibrium studies demonstrate that Na + enrichment of clinoptilolite is beneficial in respect to metal uptake for all metals, except Cr3+, which is shown to have the same equilibrium behavior in both materials. Kinetic study shows that diffusion coefficients are in the range of 0.16 to 9×10-9 cm 2/s, and are not always improved in Na-rich form of clinoptilolite. The effect of temperature on diffusion coefficients is also examined, and Arrhenius activation energy is determined to be in the range of 3.02 to 13.9 kcal/mol, for all metals and materials, except Cu2+, which have extremely low activation energy in the natural sample, equal to 0.04 kcal/mol.

Original languageEnglish
Pages (from-to)570-576
Number of pages7
JournalJournal of Colloid and Interface Science
Issue number2
Publication statusPublished - Jul 15 2004


  • Activation energy
  • Clinoptilolite
  • Diffusion coefficients
  • Distribution coefficients
  • Heavy metals
  • Ion exchange

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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