Enhancement of NOx adsorption performance on zeolite via a facile modification strategy

• Published in: Journal of hazardous materials 2023-02, Vol.443, p.130225-130225, Article 130225
• Main Authors: Liu, Yingshu, Wu, Xiaoyong, Yang, Xiong, Tao, Haiyang, Li, Jinjuan, Zhang, Chuanzhao, Yang, Ralph T., Li, Ziyi
• Format: Article
• Language: English
• Subjects: Adsorption; Desorption; Incipient-wetness impregnation; Nitrogen oxides; Zeolite
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.130225

Adsorption is a promising technology for simultaneously capturing nitrogen oxides (NOx) from flue gases and recycling NO2 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 NOx 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 NOx feed concentrations and room temperature, the IM sample renders a record NOx adsorption capacity (qt,NOx) of 0.878 mmol/g from dry gas stream on zeolites, and an applicable qt,NOx of 0.1 mmol/g from wet gas stream with a proper copper loading (2.1 wt%). The temperature programmed desorption of NOx on the optimal IM sample saturated with NOx from wet gas stream exhibit primary peak temperature lower than reported Cu-ZSM-5 and significant NO2 proportion (72.6 %) in desorbed NOx. Deeper insights into advantageous NOx oxidative adsorption over the properly-loaded Cu-ZSM-5 in terms of diverse adsorbate states and competitiveness towards H2O 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 NOx adsorption capacity at sub-1000 ppm dry gas feed on zeolites is obtained.•Applicable NOx adsorption capacity at wet feed is gained on properly-loaded Cu-ZSM-5.•Lower NOx desorption temperature and higher NO2 proportion in desorbed gas are shown.•Advantageous NOx oxidative adsorption competing with H2O on Cu-ZSM-5 is revealed.