Adsorption of ethylene and carbon dioxide binary systems on active carbon: Experiment and model

The adsorption isotherms of ethylene and carbon dioxide binary system on active carbon were studied by using the gravimetric method, and the isotherms of ethylene, carbon dioxide and their binary mixture systems on active carbon were determined by intelligent gravimetric analyzer (IGA). The double Langmuir (DL) model was applied to study the adsorption of the pure gas, and the DL model combined with the ideal adsorbed solution theory (IAST) was used to predict the adsorption isotherms of the binary system. It was found that the combined method (DL-IAST) can be applied to describe the adsorption isotherms of adsorbing the binary system of C ₂H ₄ and CO ₂ on active carbon perfectly. For the binary systems with higher molar fraction of C ₂H ₄, their adsorption isotherms predicted by IAST agree with the experimental data better than that predicted for the binary systems with lower molar fraction of C ₂H ₄. The calculated results indicate that the adsorption selectivity of C ₂H ₄ is higher when the molar fraction of C ₂H ₄ in the binary system or the used adsorption pressure is lower. It can be concluded that the DL-IAST can be used to describe the adsorption isotherms and to calculate the C ₂H ₄ adsorption selectivity for the adsorption of C ₂H ₄ and CO ₂ binary systems on active carbon.