title: Ni(2+) and H(2)PO(4)(-) uptake properties of compounds in the CaTiO(3)-CaFeO(2.5) system.
abstract: A batch method was used to investigate the uptake of heavy metal cations and anions by the compounds in the CaTiO(3)-CaFeO(2.5) system, in which a series of oxygen vacancies was systematically introduced into a perovskite structure as the x-value of Ca(Fe(x)Ti(1-x))O(3-x/2) was increased. Samples of CaTiO(3), CaFe(0.1)Ti(0.9)O(2.95), CaFe(0.5)Ti(0.5)O(2.75), CaFe(0.67)Ti(0.33)O(2.67) and CaFeO(2.5) were prepared by solid mixing (SM), co-precipitation (CP) and gel evaporation (GE) methods. The resulting samples were calcined at temperatures between 400 and 1000 °C. The target crystalline phases differed according to the preparation method, but in most cases were formed at 700-800 °C. The Ni(2+) sorption isotherms of all the samples were fitted better by the Langmuir model than by the Freundlich model, while in the case of H(2)PO(4)(-) sorption isotherms, these were better fitted by the latter model. The uptake ability increased with increasing x value of the samples. The maximum values for the saturated sorption of Ni(2+) (Q(0)(Ni(2+)) = 2.83 mmol/g) and H(2)PO(4)(-) (K(F)(H(2)PO(4)(-)) = 2.95 mmol/g) were achieved for x = 1 (i.e. CaFeO(2.5)) sample.
authors.affiliation: Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, O-okayama, Meguro, Tokyo 152-8552, Japan. popa.c.aa@m.titech.ac.jp
authors.forename: Catalin
authors.initials: C
authors.lastname: Popa
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Kameshima
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Isobe
authors.forename: Akira
authors.initials: A
authors.lastname: Nakajima
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Okada
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007501:Iron / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010756:Phosphoric Acids / Q000737:chemistry*; D013816:Thermodynamics; D014025:Titanium / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D010087:Oxides; D010756:Phosphoric Acids; D009532:Nickel; C016538:lime; D014025:Titanium; D007501:Iron; C030242:phosphoric acid