Non-isothermal solid state reaction kinetics of sol-gel derived zirconium phosphate from thermogravimetric data

Thermal transformation of polyvalent zirconium phosphate containing alpha and gamma zirconium phosphate as crystalline phases has drawn immense scientific and industrial attention in deriving advanced materials such as selective ion exchanger, acid catalyst, protonic conductor, glass-ceramic and novel functionalized ceramic. Thermal transformation of sol-gel derived zirconium phosphate was studied employing simultaneous differential thermal analysis (TG-DTA) in static air at different heating rates 5, 7.5 and 10 K min(-1) respectively. Kinetics of multistage transformation of synthesized zirconium phosphate under non-isothermal condition were interpreted and correlated by isoconversional Flynn-Wall-Ozawa (FWO) and model-free Kissinger methods. Kinetic parameters like pre-exponential factor and activation energy for conversion computed by both the methods were observed well consistent although FWO method exhibited more reliability and accuracy. Malek method was used to elucidate the thermal decomposition mechanism of synthesized zirconium phosphate. The research results showed that the transformation of synthetic zirconium phosphate under non-isothermal condition was governed by contracting volume kinetic mechanis m.