MECHANISM OF AMMONIA ADSORРTION ON ZEOLITE CaA (М-34) IN THE THEORY OF VOLUME FILLING OF MICROРORES

This article presents the logarithmic and relative pressure values of the ammonia adsorption isotherm obtained from eхperiments conducted at 303 K on the synthetic zeolite CaA (M-22). The isotherm values were obtained through the utilisation of an advanced adsorption microcalorimetric method, which was conducted in conjunction with a universal high-vacuum apparatus. The adsorption isotherm was determined volumetrically within the pressure range of 10⁻⁵ to 467 torr in the universal high-vacuum system. The equilibrium pressure values were used to initially calculate the differential values of Gibbs free energy, which were then used to derive a three-term mathematical equation of the sorption process based on the general equation of the volumetric filling theory of micropores (VMOT). The theoretical values were shown to correspond fully with the eхperimental data. It was demonstrated that the quantity of adsorption varies depending on the amount of sodium and calcium cations in the zeolite composition, as determined by the mathematical equation of the isotherm. The sorption mechanism and the regularities of ammonia molecules filling the zeolite volume from the initial to the eхperimental region were identified for ammonia molecule adsorption on CaA (M-22) zeolite.