Preparation of alumina-iron oxide compounds by gel evaporation method and its simultaneous uptake properties for Ni2+, NH4+ and H2PO4-

Fahmida Gulshan, Yoshikazu Kameshima, Akira Nakajima, Kiyoshi Okada

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


Fe2O3/Al2O3 powders with a range of Fe/Al compositions were prepared by a gel evaporation method to investigate the effect of alumina on the product phases, magnetic properties and simultaneous adsorption of Ni2+ (a model heavy metal cation), NH4+ (a model eutrophication-related cation) and H2PO4- (a model harmful anion). Precursor gels were prepared by dissolving Fe(NO3)3·9H2O and Al(NO3)3·9H2O in ethylene glycol, evaporating to dryness, grinding and heating at 300-1000 °C for 5 h. The crystalline products were γ-Fe2O3 (maghemite), formed at 300-600 °C, or α-Fe2O3 (hematite) and AlFeO3, formed >600 °C. The temperatures of the phase change from γ-Fe2O3 to α-Fe2O3 increased with increasing alumina additions. The resulting lattice parameters suggest that Al3+ is incorporated into these phases up to about 15 mol.% at 300 °C, falling to 11 mol.% in the γ-Fe2O3 formed at 600 °C. The α-Fe2O3 formed at 700 °C contained 6 mol.% Al, increasing to 14 mol.% at 1000 °C. The magnetic properties of the samples were measured using a vibrating sample magnetometer. The saturation magnetization values of the γ-Fe2O3-containing samples increased with the addition of alumina to a maximum value of 61 emu/g in the sample containing 95 mol.% Fe2O3 heated at 400 °C. The simultaneous adsorption of Ni2+, NH4+ and H2PO4- from water was investigated by a batch method. The highest adsorption values were found for the sample containing 80 mol.% Fe2O3 heated at 600 °C, which contained both γ-Fe2O3 and α-Fe2O3. It was therefore concluded that the addition of alumina to iron oxide affects the crystalline phases and phase changes, and enhances the simultaneous cation and anion uptake ability of the materials.

Original languageEnglish
Pages (from-to)697-702
Number of pages6
JournalJournal of Hazardous Materials
Issue number1-3
Publication statusPublished - Sept 30 2009
Externally publishedYes


  • Alumina addition
  • Ion adsorption
  • Iron oxide
  • Magnetic property

ASJC Scopus subject areas

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


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