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    Item type:Publication,
    Kinetics and thermodynamics of thermal decomposition of synthetic AlPO 4•2H2O
    (2009-12-01)
    Boonchom, Banjong
    ;
    Danvirutai, Chanaiporn
    The non-isothermal kinetics of dehydration of AlPO<inf>4</inf>•2H <inf>2</inf>O was studied in dynamic air atmosphere by TG-DTG-DTA at different heating rates. The result implies an important theoretical support for preparing AlPO<inf>4</inf>. The AlPO<inf>4</inf>•2H<inf>2</inf>O decomposes in two step reactions occurring in the range of 80-150 °C. The activation energy of the second dehydration reaction of AlPO<inf>4</inf>•2H<inf>2</inf>O as calculated by Kissinger method was found to be 69.68 kJ mol<sup>-1</sup>, while the Avrami exponent value was 1.49. The results confirmed the elimination of water of crystallization, which related with the crystal growth mechanism. The thermodynamic functions (ΔH*, ΔG*and ΔS*) of the dehydration reaction are calculated by the activated complex theory. These values in the dehydration step showed that it is directly related to the introduction of heat and is non-spontaneous process. © 2009 Akadémiai Kiadó, Budapest, Hungary.