Adsorption properties of nitrogen monoxide on silver ion-exchanged zeolites
- Jilin Univ., Changchun (China). Dept. of Chemistry
- Hokkaido Univ., Sapporo (Japan). Catalysis Research Center
The removal of nitrogen oxides (NO{sub x}) which cause acid rain and air pollution is an important global environmental problem which needs to be solved soon. The adsorption properties of nitrogen monoxide (NO) on various silver ion-exchanged zeolites were examined by adsorption-desorption measurements in a fixed bed flow apparatus. Both reversible (q{sub rev}) and irreversible (q{sub irr}) adsorption of NO is dependent on the aluminum content in the zeolites and the zeolite structure. The amounts of reversible and irreversible adsorption of NO per silver ion increased with decreasing aluminum content of the zeolites and were constant, independent of the ion exchange level for ZSM-5 zeolites, but increased with the ion exchange level for mordenite zeolites (MOR). It was also found that the adsorption properties are dependent on the temperature and pressure of adsorption: q{sub irr} and q{sub rev} of Ag-MOR increased with decreasing absorption temperature and increasing adsorption pressure. Furthermore, the influence of preadsorbed gases on the Ag-MOR zeolite was investigated, and an enhancement of q{sub rev} was observed when NO{sub 2} was preadsorbed. The NO species adsorbed on the Ag-MOR zeolite were characterized by infrared (IR). Most of the reversibly adsorbed NO species are NO{sup {delta}+} and some N{sub 2}O adsorbed on Ag{sup +}, and the irreversibly adsorbed NO species are some N{sub 2}O, NO{sup {delta}+}, and a small amount of NO{sup {delta}{minus}}, NO{sub 2}{sup {delta}+}.
- OSTI ID:
- 347495
- Journal Information:
- Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 4 Vol. 11; ISSN CMATEX; ISSN 0897-4756
- Country of Publication:
- United States
- Language:
- English
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