The use of the IKP method for evaluating the kinetic parameters and the conversion function of the thermal decomposition of NaHCO<inf>3</inf> from nonisothermal thermogravimetric data

Abstract

Three linear isoconversional methods (Friedman, Flynn-Wall-Ozawa, and Kissinger-Akahira-Sunose) and the invariant kinetic parameters (IKP) method were used in order to examine the kinetics of the nonisothermal decomposition of a sodium bicarbonate (NaHCO3). The objective of the paper is to show the usefulness of the IKP method to determine both the kinetic parameters and the kinetic model of the investigated process. The activation energy (E a) value obtained by the IKP method is in good agreement with the values obtained by isoconversional methods. The IKP method associated with the criterion of coincidence of kinetic parameters for all heating rates led us to the following kinetic triplet: Ea = 95.5 kJ mol-1, A = 2.65 × 1010 min-1, and conversion function f(α) = (1 - α) (first-order reaction model, F1). © 2007 Wiley Periodicals, Inc.