Thermokinetic investigation of acid sites of the vermiculite doped lanthanum

摘要

It is widely recognised that the activation energy (Ea) is involved in the process of thermal decomposition; it allows the stability of the material to be better understood. The Ozawa method is an efficient tool for obtaining the kinetic parameters involved in the process of thermal decomposition. This method is based on measuring the thermal energy associated with the decomposition mass percentage related to temperature that is obtained using thermogravimetric analysis (TGA) at different temperatures. The thermogravimetric curves of vermiculite samples at different temperatures showed a shift at higher temperature associated with increased heating rate values. However, when a small heating ratio is used, this energy is released in the system on a larger time interval, allowing the sample to absorb this energy more efficiently, which results in a greater mass removal at lower temperatures. The interactions of acid sites with the probe molecule showed a quantitative relation to increasing the lanthanum doping, and the samples with higher doping lanthanum showed higher value of activation energy associated with the desorption of the probe molecule.