New methodology for the measurement and analysis of adsorption dynamics: Butane on activated carbon

The dynamic uptakes of n-butane on Westvaco BAX-1100 activated carbon were measured over the temperature and pressure ranges of 283-383 K and similar to3-1000 Torr, respectively. The experimental uptakes were used to determine the overall linear driving force (LDF) mass-transfer coefficients and their statistically significant dependences on the operating conditions (temperature and loading). Moreover, the effects of temperature on the order of the parabolic concentration profiles inside the adsorbent particle were determined, and the role of these effects in providing the proper description of the energy-activated mechanism of diffusion was established over the studied range of operating conditions. Overall, it was indicated that the energy barrier for diffusion is independent of temperature and that it increases with increasing adsorbent surface coverage with the adsorbate. Nevertheless, a transient state of diffusion was indicated in which an apparent energy barrier for diffusion appears to depend on temperature.