Adsorption of trace gases (propane, butane and Freon-12) from carrier gases (helium, nitrogen and carbon dioxide) on activated carbon

Abstract

Adsorption at ppm concentrations of propane, n-butane and dichlorodifluoromethane (Freon-12) gases and their mixtures from carrier gases helium, nitrogen, and carbon dioxide was measured on activated carbon at atmospheric pressure and 290 K. The experimental data are compared with predictions for an ideal-adsorbed-solution based upon single-gas (SG) and single-solute (SS) standard states. The SG standard states underestimate the adsorption of trace components with an average error of 25%. Average errors from SS standard states are only 8%, but new experimental isotherms are required for each trace component if the carrier gas is changed. Adsorbed-phase non-idealities observed for these systems can be explained by differences in size between large trace-gas molecules and small carrier-gas molecules.