Predicting Gas‐Phase Adsorption Equilibria of Volatile Organics and Humidity

Abstract

Several thermodynamic models that may be used to predict single and binary adsorption equilibria for organic vapors and competitive interactions between water vapor and a single organic vapor were developed and tested. The low organic vapor concentrations and humidities that were examined are similar to those that would be encountered in air stripping tower air emissions. The Dubinin‐Radushkevich (D‐R) equation was shown to predict single‐component adsorption equilibria for trichloroethene (TCE) and tetrachloroethene (PCE) using a reference isotherm which was conducted on toluene and physical properties of TCE and PCE. Both the Polanyi potential theory and ideal adsorbed solution theory (IAST) were shown to predict binary adsorption equilibria for TCE and PCE using single component isotherm data. The competitive interactions between water vapor and TCE were predicted using TCE isotherm data (which was conducted at low relative humidities), a water vapor isotherm, and the pore size distribution of the carbon.