Direct observation of grafting interlayer phosphate in Mg/Al layered double hydroxides

Journal Article · Wed Feb 15 00:00:00 EST 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.11.034· OSTI ID:21612900

Shimamura, Akihiro ^[1]; Kanezaki, Eiji ^[2]; Jones, Mark I ^[3]; Metson, James B ^[1]

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1. School of Chemical Sciences, University of Auckland 23 Symonds St, 1142 Auckland (New Zealand)
2. Department of Chemical Science and Technology, Graduate School of Advanced Technology and Science, University of Tokushima, 2-1 Minamijosanjima, Tokushima 770-8506 (Japan)
3. Department of Chemical and Material Engineering, University of Auckland, 20 Symonds St, 1142 Auckland (New Zealand)

The grafting of interlayer phosphate in synthetic Mg/Al layered double hydroxides with interlayer hydrogen phosphate (LDH-HPO{sub 4}) has been studied by XRD, TG/DTA, FT-IR, XPS and XANES. The basal spacing of crystalline LDH-HPO{sub 4} decreases in two stages with increasing temperature, from 1.06 nm to 0.82 nm at 333 K in the first transition, and to 0.722 nm at 453 K in the second. The first stage occurs due to the loss of interlayer water and rearrangement of the interlayer HPO{sub 4}{sup 2-}. In the second transition, the interlayer phosphate is grafted to the layer by the formation of direct bonding to metal cations in the layer, accompanied by a change in polytype of the crystalline structure. The grafted phosphate becomes immobilized and cannot be removed by anion-exchange with 1-octanesulfonate. The LDH is amorphous at 743 K but decomposes to Mg{sub 3}(PO{sub 4}){sub 2}, AlPO{sub 4}, MgO and MgAl{sub 2}O{sub 4} after heated to 1273 K. - Graphical abstract: The cross section of the synthetic Mg, Al layered double hydroxides in Phase 1, with interlayer hydrogen phosphate Phase 2, and with grafted phosphate, Phase 3. Highlights: Black-Right-Pointing-Pointer The grafting of hydrogen phosphate intercalated Mg/Al-LDH has been studied. Black-Right-Pointing-Pointer The basal spacing of crystalline LDH-HPO{sub 4} decreases in two stages with increasing temperature. Black-Right-Pointing-Pointer The first decrease is due to loss of interlayer water, the second is attributed to phosphate grafting. Black-Right-Pointing-Pointer The grafted interlayer phosphate becomes immobilized and cannot be removed by anion-exchange.

• OSTI ID: 21612900
• Journal Information: Journal of Solid State Chemistry, Vol. 186; Other Information: DOI: 10.1016/j.jssc.2011.11.034; PII: S0022-4596(11)00640-2; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
ALUMINIUM PHOSPHATES
CROSS SECTIONS
FOURIER TRANSFORMATION
HEAT TREATMENTS
HYDROXIDES
INFRARED SPECTRA
ION EXCHANGE
LAYERS
MAGNESIUM OXIDES
MAGNESIUM PHOSPHATES
PHOSPHORIC ACID
WATER
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY
X-RAY SPECTROSCOPY
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
ELECTRON SPECTROSCOPY
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INORGANIC COMPOUNDS
INTEGRAL TRANSFORMATIONS
MAGNESIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
SCATTERING
SPECTRA
SPECTROSCOPY
TRANSFORMATIONS