Kinetics and Thermodynamics of Zinc Phosphate Hydrate Synthesized by a Simple Route in Aqueous and Acetone Media

Zinc phosphate (Zn-3(PO4)(2)center dot 4H(2)O) was prepared by a simple route using ZnO and H3PO4 in aqueous and acetone media at ambient temperature. Zn-3(PO4)(2)center dot 4H(2)O decomposes to Zn-3(PO4)(2) by three dehydration reactions, as revealed by thermal analytical (TG/DTG/DTA) and differential scanning calorimetry (DSC) techniques. The synthesized Zn-3(PO4)(2)center dot 4H(2)O and its dehydration product Zn-3(PO4)(2) were characterized by powder X-ray diffraction, Fourier transfer infrared, and scanning electron microscopy. Kinetic triplet parameters (activation energy, E; preexponential, A; Avrami exponent, n) and thermodynamic functions (Delta H*, Delta G*, and Delta S*) of three dehydration reactions are calculated by DSC experiments. Evaluation and control of the specific characteristics of three dehydration processes of Zn-3(PO)(2)center dot 4H(2)O are essentially important in the variously oriented studies, which were discussed from the viewpoints of thermal stability based on kinetics and thermodynamics.