Hybrid Cu-Fe/ZSM-5 Catalyst Prepared by Liquid Ion-Exchange for NOx Removal by NH3-SCR Process

Tuan Doan,Minh Thang Le,Thanh Huyen Vuong,Dat Nguyen,Anh Dang,Huyen Pham Thanh,Jamal Rafique

doi:10.1155/2021/5552187

Tuan Doan, Minh Thang Le + Show 5 more

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https://doi.org/10.1155/2021/5552187

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Abstract

A series of Cu/ZSM-5, Fe/ZSM-5, and Cu-Fe/ZSM-5 catalysts (Si/Al in ZSM-5 = 25) were prepared by different metal loadings using the liquid ion-exchange method. Several characterization methods were conducted to explore the effects of metals on the physical and chemical properties of catalysts. Meanwhile, the electron paramagnetic resonance method is also used to assess the copper and/or iron elements’ coordination and valence state at intersections or in channels of ZSM-5. The metal-loading effects of all catalysts on the catalytic activities were studied for the removal of NOx in a fixed-bed flow reactor using selective catalytic reduction with ammonia (NH3-SCR). The results showed that the iron’s addition could markedly broaden the operation temperature range of the Cu/ZSM-5 catalyst for NH3-SCR between 200 and 550°C due to the presence of more isolated Cu2+ ions as well as additional oligomeric Fe3+ active sites and FexOy oligomeric species. This paper gives a facile and straightforward way to synthesize the practical-promising catalyst applied in NH3-SCR technology to control NOx emissions.

Highlights

Under industrialization with the industry’s rapid growth, environmental problems are accumulating and increasing swiftly, making the community concerned
The aqueous ionexchange method was applied for preparing all the metal catalysts. e Cu-Fe/ZSM-5, Cu/ZSM-5, and Fe/ZSM-5 catalysts were characterized by various techniques to determine the physicochemical properties. e main objective of this study focuses on the following contents: (i) e effects of Cu, Fe, and codoping Cu-Fe supported on ZSM-5 zeolite to their catalyst properties were clarified (ii) the NH3-selective catalytic reduction (SCR) activity and the hydrothermal durability of catalysts were conducted
In JCPDS data cards (JCPDS 42-0024), which show peak diffractions at 7.92°, 8.80°, 14.78°, 23.10°, 23.90°, and 24.40°, the prevalent diffraction peaks for commercial ZSM5 can be simple to index into the standard parameters for MFI topology. e X-ray diffraction (XRD) patterns of all catalysts have included all characteristic peaks corresponding to ZSM-5, suggesting that ZSM-5 does not destroy its original form during the process of aqueous ion-exchange and calcination [20]

Summary

Introduction

Under industrialization with the industry’s rapid growth, environmental problems are accumulating and increasing swiftly, making the community concerned. To accommodate exhaust emissions from both light and heavy diesel engines and to increase the N2 selectivity of the NOx reduction reaction, the catalyst must have a wide operating temperature range (i.e., from 100 to 600°C). Is study aims to clarify the application of copper-iron bimetallic-supported commercial ZSM-5 for the NH3-SCR catalyst. Cu-Fe/ZSM-5 samples were compared with single metal on ZSM-5 (Cu/ZSM-5 and Fe/ZSM5), thereby clarifying supplementary advantages, reciprocal effects of both copper and iron to catalytic properties, and the ability to widen the operating temperature range for deNOx with NH3 reductant. (i) e effects of Cu, Fe, and codoping Cu-Fe supported on ZSM-5 zeolite to their catalyst properties were clarified (ii) the NH3-SCR activity and the hydrothermal durability of catalysts were conducted

Experimental

Results and Discussion

Conclusion