Dehydration behavior of synthetic Al0.5Fe0.5PO 4·2.5H2O

Boonchom, Banjong; Vittayakorn, Naratip

doi:10.1021/je100096e

Dehydration behavior of synthetic Al0.5Fe0.5PO 4·2.5H2O

Author(s)

Boonchom, Banjong

Vittayakorn, Naratip

Date Issued

September 9, 2010

Type

Article

DOI

10.1021/je100096e

Abstract

The dehydration behavior of the experimentally produced Al 0.5Fe0.5PO4·2.5H2O solid solution is assessed from thermogravimetrical (TG, differential thermogravimetric, DTG, and differential thermal analysis, DTA) and differential scanning calorimetry (DSC) analyses. The dehydration proceeded through a well-defined step at low temperatures (< 300 °C), which corresponds to the loss of 2.5 water molecules. The fluctuating dependence of the activation energies on fraction mass loss (α) for the dehydration reaction of Al 0.5Fe0.5PO4·2.5H2O calculated through isoconversional methods (Ozawa and the Kissinger-Akahira-Sunose) indicates the existence of a complex multistep mechanism. The Avrami exponent value of 1.11 is indicative of one-dimensional growth as a phase boundary mechanism. The thermodynamic functions (ΔH^*, ΔG^*, and ΔS^*) of the dehydration reaction calculated from the DSC technique are discussed for the first time. © 2010 American Chemical Society.

Citation

Journal of Chemical and Engineering Data, 55(9), 3307-3311, 2010