Mechanism of NO Adsorption on H-ZSM-5 under Aerobic Atmosphere

Abstract

NO adsorption behavior on H-ZSM-5 was investigated using a fixed-bed reactor and the adsorption mechanism was studied by temperature programmed desorption (TPD), in-situ Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis. Results showed that heat releasing area (HRA) occurred at the beginning of NO and O₂ co-adsorption on H-ZSM-5, and after the disappearance of HRA, zeolites with different silicate-aluminum ratios showed different adsorption efficiency. The impurities in flue gas had a negative effect on the adsorption of NO and the influence could be ranked in descending order as follows: SO₂ > H₂O > CO₂. TPD and FTIR analyses suggested that nitrates were formed during exposure of zeolites to NO without O₂ and different kinds of nitrogen oxides were observed after O₂ was added into the system. An adsorption mechanism involving rapid oxidation of NO was proposed to explain the NO adsorption behavior under aerobic atmosphere. This work may be crucial for understanding the catalysis mechanism of metal ion-based ZSM-5 zeolites and the design of proper catalyst supporter.

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Wuhan University of Technology and Springer-Verlag GmbH Germany, Part of Springer Nature