Adsorption Equilibria of Ammonia Gas on Inorganic and Organic Sorbents at 298.15 K

The adsorption equilibria of ammonia gas on various inorganic and organic sorbents were determined at 298.15 K in a pressure range of 0−101 kPa using a static volumetric apparatus. The zeolite sorbents were 4A, 5A, 13X, dealuminated faujasite, dealuminated pentasil, and clinoptilolite. To illustrate the differences between commercial grades, the 5A and 13X zeolites were obtained from three suppliers. Other inorganic sorbents were three aluminas and three silica gels. Organic sorbents were two activated carbons, charcoal, and two polymeric sorbents (sulfonated and nonsulfonated). The nonlinear experimental equilibrium data were fitted to the Langmuir, Freundlich, Langmuir−Freundlich, and Toth isotherm models. The Henry model was used for the linear equilibrium data. The equilibria of all of the sorbents, with the exception of sulfonated polymeric and dealuminated pentasil zeolite sorbents, provide an accurate correlation with the isotherm models over the entire pressure range.