Fatma Tuğçe ŞENBERBER, Emek MÖRÖYDOR DERUN

Thermal kinetics and thermodynamics of the dehydration reaction of Mg3(PO4)2·22H2O

Mg3(PO4)2·22H2O lost its crystal water in the temperature range of 40 - 200°C and the calcined sample was identified as Mg3(PO4)2, was a notable for its further treatments in optical and electrical applications. Dehydration process was studied using non-isothermal thermogravimetry (TG) applying model-fitting method. Different mechanism models (chemical reaction order, diffusion and phase interfacial reaction) were applied. The activation energies calculated for the dehydration reaction; and average of activation energy was found as 160 kJ/mol. The better kinetic model of the dehydration reaction for Mg3(PO4)2·22H2O was selected as F3 (chemical reaction - third order). The thermodynamic functions (ΔH, ΔG and ΔS) of the dehydration reaction were calculated by the activated complex theory and found that the process was endothermic, non-spontaneous and fast.

Keywords:

Magnesium phosphate, decomposition kinetic thermal behaviour, thermodynamic,

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