Phosphate-intercalated CaFe-layered double hydroxides: Crystal structure, bonding character, and release kinetics of phosphate

Myong A. Woo, Tae Woo Kim, Mi Jeong Paek, Hyung Wook Ha, Jin Ho Choy, Seong Ju Hwang

Research output: Contribution to journalArticle

71 Citations (Scopus)

Abstract

The nitrate-form of CaFe-layered double hydroxide (CaFe-LDH) was synthesized via co-precipitation method, and its phosphate-intercalates were prepared by ion-exchange reaction. According to X-ray diffraction analysis, the CaFe-LDHNO3- compound and its H2PO 4--intercalate showed hexagonal layered structures, whereas the ion-exchange reaction with HPO42- caused a frustration of the layer ordering of LDH. Fe K-edge X-ray absorption spectroscopy clearly demonstrated that the CaFe-LDH lattice with trivalent iron ions was well-maintained after the ion-exchange with HPO4 2- and H2PO4-. Under acidic conditions, phosphate ions were slowly released from the CaFe-LDH lattice and the simultaneous release of hydroxide caused the neutralization of acidic media. Fitting analysis based on kinetic models indicated a heterogeneous diffusion process of phosphates and a distinct dependence of release rate on the charge of phosphates. This study strongly suggested that CaFe-LDH is applicable as bifunctional vector for slow release of phosphate fertilizer and for the neutralization of acid soil.

Original languageEnglish
Pages (from-to)171-176
Number of pages6
JournalJournal of Solid State Chemistry
Volume184
Issue number1
DOIs
Publication statusPublished - 2011 Jan 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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