Studies on non-isothermal and isothermal dehydration kinetics of FePO4•2H2O

In dynamical air atmosphere, the non-isothermal and isothermal thermal decomposition of FePO4 center dot 2H(2)O have been studied by TG, DTG, DSC and XRD techniques. The studies clearly indicate that the decomposition occurs in a single reaction step: the dehydration of FePO4 center dot 2H(2)O to FePO4. The model-free methods together with multivariate non-linear regression approach were employed to determine the activation energy (E), the pre-exponential factor (A) and the kinetic model function (mechanism) of the dehydration reaction. The results show that the most probable kinetic model of dehydration for FePO4 center dot 2H(2)O is well described by the nth-order reaction (Fn), corresponding to the differential function f(alpha)=(1 - alpha)(n). For non-isothermal reaction, the values of n, E and In(A/s(-1)) are 0.63, 81.10 kJ mol(-1) and 16.79, respectively. For isothermal reaction, the values of n, E and In(A/s(-1)) are 0.25, 81.47 kJ mol(-1) and 16.70, respectively. (C) 2012 Elsevier B.V. All rights reserved.