0000000000019152
AUTHOR
Abdellah Elmchaouri
Données expérimentales et modélisation d’adsorption des systèmes N2(g)/montmorillonite potassique de Camp-Berteau et N2(g)/hydrotalcite carbonatée
Resume In this paper capacities of adsorption of nitrogen onto two clays at 77 K are compared and analyzed. One system is a montmorillonite of Camp-Berteau saturated by potassium cation and the second one is an hydrotalcite saturated by carbonate anion. Adsorbed amounts have been obtained using a volumetric technique. So it is shown that the smectite adsorbed more than the hydrotalcite at the same relative pressure of nitrogen. The modelling of experimental data by various theories of adsorption as de Brunauer, Emmett et Teller (BET) and t-method are used to calculate the specific surface and to have access to the porosity of these materials at 77 K. Then it is shown that the adsorption of …
Water vapour adsorption onto Ca2+ Camp–Berteau montmorillonite and comparison with properties of Na+ sample
Abstract In this paper, we present an analysis of the adsorbed amounts and adsorption heats of water vapour of Ca2+ Camp–Berteau montmorillonite. Measurements were obtained at 298 K using thermogravimetry and calorimetry as a function of relative pressure and the study was completed by the adsorption of nitrogen at 77 K. Experimental data were analysed with BET and t-method theories and compared with those of the Na+ sample. A correlation was shown between models and two domains observed on the calorimetric curves. These domains have been attributed to a multilayer equivalent adsorption. However, the determination of the surface area of clays remains a difficulty. So, the areas of interlaye…
Study of the Pore Network of Dealuminated Faujasites by Water Vapor Adsorption
Summary The adsorption and desorption isotherms of water vapor are drawn at 25°C for dealuminated HY zeolites upon framework Si/Al ratio. The isotherms are compared to that of the parent NaY zeolite. The isotherm changes in shape from the type I to the type IV with an hysteresis loop changing from the type H 4 to the type H 2 , as increases the Si/Al ratio. The POLANYI-DUBININ theory is used to determine the micropore volume accessible to water. It decreases with increasing Si/Al ratios, down to zero at a Si/Al ratio of 35. Such a result is accounted by the adsorption on the hydrophilic centers which are the cations (H + ) associated with the structural aluminium ions, each cation being coo…