Uptake properties of Ni2+ by nCaO·Al2O 3·2SiO2 (n = 1-4) prepared from solid-state reaction of kaolinite and calcite

Vinay Kumar Jha, Yoshikazu Kameshima, Akira Nakajima, Kiyoshi Okada, Kenneth J.D. MacKenzie

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


A series of nCaO·Al2O3·2SiO2 samples (n = 1-4) were prepared by solid-state reaction of mechanochemically treated mixtures of kaolinite and calcite fired at 600-1000°C for 24 h. All the samples were X-ray amorphous after firing at 600-800°C but had crystallized by 900°C. The main crystalline phases were anorthite (n = 1), gehlenite (n = 2 and 3) and larnite (n = 4). The uptake of Ni2+ by nCaO·Al2O3·2SiO2 samples fired at 800 and 900°C was investigated at room temperature using solutions with initial Ni2+ concentrations of 0.1-50 mmol/l. Amorphous samples (fired at 800°C) showed a higher Ni2+ uptake capacity than crystalline samples (fired at 900°C). Ni2+ uptake was found to increase with increasing of CaO content. Amorphous 4CaO·Al 2O3·2SiO2 showed the highest Ni 2+ uptake capacity (about 9 mmol/g). The Ni2+ uptake abilities of the present samples are higher than those of other materials reported in the literature. Since the sorbed Ni2+/released Ca 2+ ratios of these samples are close to unity, ion replacement of Ni2+ for Ca2+ is thought to be the principal mechanism of Ni2+ uptake by the present samples.

Original languageEnglish
Pages (from-to)281-287
Number of pages7
JournalJournal of Hazardous Materials
Issue number1-3
Publication statusPublished - Aug 31 2005
Externally publishedYes


  • CaO-AlO-SiO system
  • Calcite
  • Kaolinite
  • Mechanochemical treatment
  • Ni uptake

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis


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