Effect of relative humidity on the adsorption of selected water-miscible organic vapors by activated carbon.

The adsorptive capacity of activated charcoal was determined experimentally for the vapors of 2-ethoxyethanol, pyridine, acetic acid, and piperidine from dry air and from air saturated with water vapor. Vapor concentrations ranged from 100 mg/m3 to at least 1000 mg/m3; the temperature was kept constant at 25°C. The reduction in the adsorptive capacity of the activated charcoal by the relative humidity over the entire range of experimental conditions was accounted for by the Hansen-Fackler modification of the Dubinin-Radushkevich equation. This procedure allows the use of the activity coefficients, which are basic thermodynamic factors often available in the literature, to estimate the effect of adsorbed moisture on the adsorption of these organic compounds from a humidified atmosphere.