High Performance, Surface Modified Carbons for Separation of Toxic Gases in Dilute Streams

Separation of trace quantities of species from gas and liquid streams is a major problem for both defense and commercial applications. The motivation for removal varies greatly in different applications. Examples include; safety (gas masks and protective clothing in chemical warfare and hazardous industrial environments), higher semiconductor yields (particularly for deep UV lithography), drinking water clean-up (such as lead), and production of UHP chemicals for electronics. Separations for these and other applications are growing rapidly as a result of increasing environmental, safety and energy regulation as well as the increased risk of chemical warfare by terrorist organizations. For the separation of species from dilute streams, the most preferred method is adsorption. Activated carbons are the preferred adsorbent because of their very high surface area and low costs. However, it is difficult to change surface chemistry of carbons to achieve enhanced selectivity, greater adsorbent capacity, greater retention and possible catalytic decomposition toxic compounds. This project explores the use of novel surface modification schemes using chemical weapons simulants and ammonia/amines as sample toxic gases/vapor. The improvement in absorber performance as a function of surface modification, base activated carbon, and water content will be demonstrated.