Ni2+ uptake by amorphous and crystalline Ca2Al 2SiO7 synthesized by solid-state reaction of kaolinite

Vinay Kumar Jha, Yoshikazu Kameshima, Kiyoshi Okada, Kenneth J.D. Mackenzie

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19 Citations (Scopus)


The uptake of Ni2+ by amorphous and crystalline gehlenite (Ca2Al2SiO7) was investigated. The Ca 2Al2SiO7 samples were prepared by solid-state reaction of mixtures of kaolinite, calcite, and aluminum hydroxide mechanochemically treated the mixture for 0-24 h and fired at 600-900°C for 24 h. The mechanochemically treated samples crystallized to form gehlenite at ≥850°C, below which temperature they were amorphous. Ni2+ uptake experiments were performed by a batch method at 25°C using a solid/solution ratio of 0.002 g ml-1 and a Ni2+ concentration of 10-4 to 5 × 10-2 M. The uptake capability increased with increasing pH > 6 and decreasing initial Ni 2+ concentration. The amorphous sample showed a higher Ni 2+ uptake than the crystalline sample, and its uptake was also higher than values reported in the literature for amorphous CaAl2Si 2O8, zeolites, gylorite, and activated carbon.

Original languageEnglish
Pages (from-to)209-215
Number of pages7
JournalSeparation and Purification Technology
Issue number2
Publication statusPublished - Dec 1 2004
Externally publishedYes


  • CaO-Alo -SiO system
  • Gehlenite
  • Kaolinite
  • Mechanochemical treatment
  • Ni uptake

ASJC Scopus subject areas

  • Analytical Chemistry
  • Filtration and Separation


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