Dehydration Kinetics of Zinc Phosphate Tetrahydrate α-Zn3(PO4)2·4H2O Nanoparticle
Abstract
TG-DTG technique and Harcourt-Esson integrated equation were used to study the dehydration process of zinc phosphate tetrahydrate α-Zn3(PO4)2·4H2O nanoparticle and its thermal decomposition kinetics. The results show that there are three stages of dehydration between 300 and 800 K during the thermal decomposition of α-Zn3(PO4)2·4H2O nanoparticle. The first stage is controlled by chemical reaction with an activation energy of 69.48 kJ·mol−1 and a pre-exponential factor of 1.77×106 s−1. The second is controlled by nucleation and growth with an activation energy of 78.74 kJ·mol−1 and a pre-exponential factor of 5.86×109 s−1. The third is controlled by nucleation and growth with an activation energy of 141.5 kJ·mol−1 and a pre-exponential factor of 1.01×1012 s−1. The kinetic compensative effects not only exist in Arrhenius equation but also in Harcourt-Esson equation. Activation energy E is dependent on both the decomposition fraction α and temperature T.
