Stability of concentration waves in gaseous pollutant traces dynamical adsorption

The mechanism of dynamical adsorption of single vapors (including VOC's and water) in activated carbon beds generally involves a transport step from the gaseous phase to the surface of carbon, followed by an equilibrium of adsorption. Numerical simulations at constant temperature and constant flow rate, described in a previous work (Carbon 2006, Aberdeen), illustrated the fact that the behavior of the pollutant concentration front, which builds into the carbon bed, is strongly dependent upon the adsorption isotherm chosen to model the phenomenon. In the present work, a uniform mathematical treatment, using the linear driving force approximation, is presented along with a simple mathematical condition for the building of a constant pattern concentration front. Implications to popular simple breakthrough models used in the field of vapor dynamical adsorption are discussed.