Removal of N{sub 2}O from industrial gaseous streams by selective adsorption over metal-exchanged zeolites

• Published in: Industrial & engineering chemistry research Vol. 39; no. 1
• Main Authors: Centi, G., Generali, P., Dall'Olio, L., Perathoner, S., Rak, Z.
• Format: Journal Article
• Language: English
• Published: United States 01.01.2000
• Subjects: ADSORPTION; AIR POLLUTION CONTROL; ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; ENVIRONMENTAL SCIENCES; INDUSTRIAL WASTES; ION EXCHANGE; MATERIALS TESTING; NITROUS OXIDE; SORPTIVE PROPERTIES; ZEOLITES
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie990360z

The behavior of ZSM5 zeolites in the acid, sodium form or ion-exchanged with various metal ions (Cs, Sr, Ba, Mg, Fe, Co, Cu, Ag, Rh, Ga, In, La, and Ce) and that of Y and X zeolites ion-exchanged with Ba ions are discussed with reference to their behavior in the adsorption of 2{sub 2}O from gaseous industrial streams containing low (<0.1--0.2%) concentrations of N{sub 2}O, to produce a concentrated (>5%) stream of N{sub 2}O for either autothermic operation of the decomposition of N{sub 2}O or use of N{sub 2}O as a selective oxidant. Ba-ZSM5 show significantly better performances than other metal-exchanged zeolites in the adsorption of N{sub 2}O, although water competes with N{sub 2}O for adsorption. However, the adsorption of N{sub 2}O is faster than that of water, and thus it is possible to adsorb N{sub 2}O even in the presence of larger (40 times higher) amounts of water in the feed. It is also shown that it is possible to have a dual-bed selective adsorption, where first water adsorbs selectively on an alumina bed and then N{sub 2}O is adsorbed on a Ba-ZSM5 bed. It is suggested that the enhanced adsorption properties of Ba-ZSM5 are related to the presence of naked Ba{sup 2+} ions that creates a strong electrostatic field within the zeolite cavities which allows the orienting of the N{sub 2}O molecule and its trapping inside the zeolite.