Adsorption Equilibrium, Kinetics, and Enthalpy of N2O on Zeolite 4A and 13X

The adsorption equilibrium, kinetics, and enthalpy of nitrous oxide adsorption on zeolites 4A and 13X were measured volumetrically at temperatures of (194, 237, and 298) K and gas pressure up to 108 kPa. It was found that zeolite 4A adsorbs more N2O than 13X in all of the conditions used. The Langmuir, Freundlich, and Toth isotherm models were employed to correlate the adsorption isotherms. N2O diffusivity in these adsorbents at 298 K was calculated from the adsorption kinetic uptake curves by using a simple micropore diffusion model. It was found that the average diffusivity values in zeolite 4A and 13X are (3.38.10(-14) and 1.05.10(-12)) m(2).s(-1) respectively. The heat of adsorption values are between (-33 and -21) kJ.mol(-1) for zeolite 4A and (-28 and -22) kJ.mol(-1) for 13X for adsorption loadings between (0.5 and 3.5) mmol.g(-1).