Adsorption of ammonia by sulfuric acid treated zirconium hydroxide

Abstract

The adsorption of ammonia on Zr(OH)4, as well as Zr(OH) 4 treated with sulfuric acid, were examined. The results show that treating Zr(OH)4 with sulfuric acid leads to the formation of a sulfate on the surface of the material, and that the sulfate contributes to the ammonia adsorption capacity through the formation of an ammonium sulfates species. Calcination of Zr(OH)4 decreases the ammonia adsorption capacity of the material and limits the formation of sulfate species. NMR and FTIR spectroscopy results are presented that show the presence of two distinct ammonium species on the surface of the material. The adsorption capacity of the materials is shown to be a complex phenomenon that is impacted by the surface area, the sulfur content, and the pH of the material. The results illustrate that Zr(OH)4, which is known to adsorb acidic gases, can be modified and used to adsorb basic gases. © 2012 American Chemical Society.