Effect of atmospheric condition on the thermal decomposition kinetics and thermodynamics of lead acetate trihydrate

Abstract

In this study thermal decomposition routes and kinetics of lead acetate triydrate are compared in inert (nitrogen) and reactive (oxygen) atmospheres by using thermogravimetric method. The decomposition proceeds with five consecutive stages in the both the atmospheres. The first four stages occur similarly in nitrogen and oxygen atmospheres and the same intermediates are formed. However, the last stage, differs according to the furnace atmosphere. The mixture of PbO and small amount metallic Pb is the final product in nitrogen atmosphere whereas the mixture of PbO and Pb 3 O 4 is the final product in oxygen atmosphere. X-ray powder diffraction method is used in identify of these products. Kinetic calculations of all stages are realized by using Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) model free methods. These methods are combined with modeling equations to find the effective model and to calculate thermodynamic parameters. It is found that all reactions show good harmony with the nucleation models although their indexes are different.