Measurements of Ammonia Adsorption Isotherms in Gas Phase
A ammonia adsorption isotherms were measured using an Autosorb 1C-VP-2( Quanthachrome, U.S.A.). The combined adsorption isotherm was first measured from 20 to 800 mmHg at 298 K after vacuum treatment at 473 K for 3 hr. After the combined adsorption isotherm was obtained, the same sample was vacuum treatment at 298K and then a weak adsorption isotherm was measured. A strong adsorption isotherm was calculated from the difference in the combine adsorption isotherm and the weak adsorption isotherm. The combined adsorption isotherm is the adsorption isotherm for the total adsorbed site. The weak adsorption isotherm is the adsorption isotherm for the adsorbed site with a weak adsorption potential such as physical adsorption desorbing at 298 K. The strong adsorption isotherm is the adsorption isotherm for the adsorbed site of the strong adsorption potential such as chemical adsorption not desorbing at
298 K.