Characterization of Acid Sites in Ion-exchanged and Solid State-exchanged Zeolites Pacific Northwest National Laboratory

Format:

Conference/Event

Author/Creator:

Ebeling, A. C., author.

Conference Name:

SAE International Fall Fuels & Lubricants Meeting & Exhibition (2001-09-24 : San Antonio, Texas, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2001

Summary:

Brønsted acidity of solution ion-exchanged and solid-state exchanged zeolites was compared for NaY, BaY, CaY, NaX, and CaX zeolites. These materials were chosen because they all exhibit catalytic activity in SCR of NOx in combination with a non-thermal plasma. Brønsted acidity was characterized qualitatively with retinol as an indicator dye. Our results show that the solid-state exchange using a chloride salt creates zeolites with lower acidity than zeolites obtained by conventional solution ion-exchange. NO2 adsorption was also found to create a significant quantity of acid sites at room temperature and a slight increase in acidity at 200°C. We speculate that the acid sites created by NO2 adsorption, because of their vicinity to metal cation sites in the zeolite, may lead to preferential reactions that lead to NOx reduction. BaY made by solution ion-exchange and BaY made by solid-state exchange using a chloride salt were tested for NOx reduction in a plasma-catalyst reactor system. Both catalysts showed similar catalytic activity. BaY prepared by solid-state exchange shows no coking due to absence of acid sites. In contrast, the BaY material prepared by conventional solution ion-exchange shows significant coke formation. Thus, the solid state exchanged BaY is a potentially more stable catalyst

Notes:

Vendor supplied data

Publisher Number:

2001-01-3571

Access Restriction:

Restricted for use by site license