Enhancement of NOx 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. [Display omitted] • Cu-ZSM-5 is prepared by incipient-wetness impregnation coupled with microwave drying. • A record NO x adsorption capacity at sub-1000 ppm dry gas feed on zeolites is obtained. • Applicable NO x adsorption capacity at wet feed is gained on properly-loaded Cu-ZSM-5. • Lower NO x desorption temperature and higher NO 2 proportion in desorbed gas are shown. • Advantageous NO x oxidative adsorption competing with H 2 O on Cu-ZSM-5 is revealed. [ABSTRACT FROM AUTHOR]