The effects of 100 ppb ozone exposure on the adsorption of 1 ppm toluene on activated carbon are presented for dry (less than 5% RH) and humid (55% RH) air. In dry air, the 10% toluene breakthrough times of granular carbon beds exposed to ozone for 208 days are 17% less than those of unexposed carbon beds. At 55% RH, the corresponding reduction in toluene breakthrough time is 78%. For a humid environment with 100 ppb ozone, filter life would be reduced by more than half compared to the expected life based on tests in the absence of ozone. This degradation is attributed to changes in carbon surface chemistry, surface area, and pore volume that occur with relatively brief exposure to the ozone.
Bibliographical noteFunding Information:
The financial support of the US National Science Foundation under grant NSF/CTS-0074667 and of the University of Minnesota’s Center for Filtration Research (CFR) are greatly appreciated. The authors would like to thank the industry members (3M Company, AAF International, Donaldson Company, Filtrauto, Fleetguard, W.L. Gore and Associates, and TSI Incorporated) of the CFR for their guidance in selecting carbons and operating conditions for this study. In particular, we acknowledge the help of Dr. Mike Strommen at 3M Company in conducting the preliminary experiments needed to design the carbon beds and Dr. Andrew Dallas and Jon Joriman at Donaldson Company who generated and helped analyze the nitrogen isotherms.
- Activated carbon
- Adsorption properties