ISOTHERM OF AMMONIA ADSORPTION IN ZEOLITE CaA (M-22)
DOI:
https://doi.org/10.61151/stjniet.v8i4.335Keywords:
adsorption, enthalpy, free energy, isotherm, pressure, relative pressure, microcalorimeter, ammoniaAbstract
Abstract.
Objective. The article presents experimentally obtained values of the adsorption isotherm of ammonia molecules in synthetic zeolite CaA (M-22) at a temperature of 303 K. Isotherm values were measured using an improved microcalorimeter connected to a universal high vacuum apparatus. The differential values of the free energy were calculated from the equilibrium values of the pressure. In CaA (M-22) zeolite, a regular relationship between the amount of adsorption and energy properties of ammonia molecules, as well as the sorption mechanism from the initial area of adsorption to the area of condensation heat of ammonia and the regularity of ammonia molecules filling the volume of zeolite were determined. Under experimental conditions, the adsorption capacity of this zeolite for ammonia was found to be 10.5 mmol/g in 1 g of zeolite. It was determined that 40% of the total adsorption is sorbed up to the equilibrium pressure of 1 torr, 50% up to 6 torr pressure, 60% up to 24 torr pressure, 65% up to 50 torr pressure and 100% at 467 torr pressure. The adsorption isotherm was recharacterized by the three-state equation of micropore volumetric saturation theory (VMOT) and it was shown that the theoretically calculated values were in perfect agreement with the experimentally obtained values.
