Thermodynamic aspects of the system water-natural phosphates: Thermal behaviour, adsorption and desorption isotherms. [French]

摘要

The thermodynamic aspects of the system water - natural phosphates from Morocco were investigated. Thermal treatments and adsorption and desorption reactions of water vapour on this material were performed. In a first part, thermogravimetric and differential thermal analyses were performed under different thermal treatments. They have allowed to characterize the different types of water in the material. In a second part, the test of the isotherms of water vapour adsorption and desorption and the measurement of the heat corresponding to the transformations, obtained experimentally by coupling both calorimetric and volumetric methods, are presented and discussed. This study allows to understand and to describe the equilibrium states between water and phosphates and to get information on the interactions of the adsorbed molecules with the material at the,various stages of the adsorption. [References: 29]