Enhancement of NO x adsorption performance on zeolite via a facile modification strategy.

Adsorption is a promising technology for simultaneously capturing nitrogen oxides (NO _x ) from flue gases and recycling NO ₂ as a profitable chemical, for which a robust and efficient adsorbent provides the key step for success in practical applications. This work reports the enhancement of NO _x adsorption performances with less cost of desorption energy on Cu-ZSM-5 zeolites prepared by a facile and rapid (690 s) modification method, the incipient-wetness impregnation coupled with microwave drying (IM). In comparisons to H-ZSM-5, Na-ZSM-5 and conventionally liquid-phase ion-exchanged counterparts under sub-1000 ppm NO _x feed concentrations and room temperature, the IM sample renders a record NO _x adsorption capacity (q _t,NOx ) of 0.878 mmol/g from dry gas stream on zeolites, and an applicable q _t,NOx of 0.1 mmol/g from wet gas stream with a proper copper loading (2.1 wt%). The temperature programmed desorption of NO _x on the optimal IM sample saturated with NO _x from wet gas stream exhibit primary peak temperature lower than reported Cu-ZSM-5 and significant NO ₂ proportion (72.6 %) in desorbed NO _x . Deeper insights into advantageous NO _x oxidative adsorption over the properly-loaded Cu-ZSM-5 in terms of diverse adsorbate states and competitiveness towards H ₂ O were gained, showing IM method a promising sorbent improvement strategy for practical use.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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