Preparation and simultaneous ion uptake properties of CaO-Fe 2O3-SiO2 compounds

Atsushi Kobayashi, Fahmida Gulshan, Yoshikazu Kameshima, Akira Nnakajima, Kiyoshi Okada

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


CaO-Fe2O3-SiO2 (CFS) compounds were prepared from mixtures of Ca(OH)2, FeOOH and SiO2 and their simultaneous uptake properties for cations and anions were investigated. The starting powders were mixed in various ratios using a planetary ball mill and heated at various temperatures in air and flowing N2 atmospheres. Amorphous compounds were formed by heating up to <600°C while hematite (α-Fe2O3) was crystallized at >600°C and calcium silicates and/or calcium iron silicates at >800°C. Simultaneous ion uptake experiments were carried out by a batch method using solutions containing same concentrations of Ni2+, NH4+ and H2PO4-. The samples heated at 600°C showed the highest ion uptake ability. The uptake abilities were higher for Ni2+ and H2PO4- than for NH 4+ and increased with increasing CaO content in the CFSs. The uptake abilities for three ions enhanced by heating the samples in flowing N2. The simultaneous uptake mechanisms are thought to be similar to those observed in the CAS compounds, i.e. ligand change (Ca2+→ Ni2+), compound precipitation and adsorption. The CFS compounds have the following advantages compared with CaO-Al2O3-SiO 2 (CAS) ; (1) higher uptake ability for phosphate ions (a model for harmful oxyanions) and (2) easy separatton of a contaminated sortent from the solution after uptake using a magnet.

Original languageEnglish
Pages (from-to)187-191
Number of pages5
JournalJournal of the Ceramic Society of Japan
Issue number1350
Publication statusPublished - Feb 2008
Externally publishedYes


  • Heavy metais
  • Magnetic property
  • Phosphate
  • Simultaneous uptake

ASJC Scopus subject areas

  • Ceramics and Composites
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry


Dive into the research topics of 'Preparation and simultaneous ion uptake properties of CaO-Fe 2O3-SiO2 compounds'. Together they form a unique fingerprint.

Cite this