Adsorption and co-adsorption of NO and water on LaCu-ZSM5

A quantitative analysis of the adsorption of NO on the zeolite previously contacted with water was made by carrying out adsorption tests at temperatures far from those activating any DeNOx reaction in a lab-scale PFR reactor. The variation of the amount of adsorbed NO with the temperature of H2O desorption has been evaluated increasing the desorption temperature from 125 to 500 degrees C after zeolite saturation with water at 125 degrees C. The total recovery of the amount of NO adsorbed on the dry zeolite demonstrated the reversibility of water deactivation. (C) 2014 Elsevier Inc. All rights reserved,

The effect of water on NO adsorption on LaCu-ZSM5 has been studied by in-situ FIR at 50 degrees C identifying for which copper sites NO adsorption competes with water. The relative thermal stability of NO and H2O ad-species have been also determined by increasing the sample temperature from 50 to 400 degrees C. Water was removed from zeolite at temperature lower than that necessary to desorb NO, as both bridged and chelating nitrates, from copper sites.