Performance of Adsorption Equations on IAS Theory for the Prediction of Adsorption Equilibrium of CH4/C2H6 and CH4/CO2 on Activated Carbons

In the present study, the adsorption equilibrium of pure methane, ethane and CO2 gases as well as their binary mixtures was studied on activated carbon prepared from macadamia nutshell (AC-MNS). The ideal adsorbed solution theory (IAST) using Langmuir (Langmuir-IAST), Sips (Sips-IAST), Toth (Toth-IAST), and Unilan (Unilan-IAST) equations along with the fast ideal adsorbed solution theory (Fast-IAST) were used to predict the binary adsorption equilibriums. Also, by investigating three adsorption cases with different degree of heterogeneity, the effect of system heterogeneity on the prediction of binary mixture adsorption in terms of model accuracy and computation time was studied. Results suggest that although the Langmuir-IAST and Fast-IAST models have attractive high speed of calculation, they do not have sufficient accuracy in predicting the experimental results. Moreover, the Sips-IAST greatly increases the computation time especially at high system heterogeneity. From the results, the Toth-IAST and Unilan-IAST models with the acceptable accuracy and computation time are proposed as powerful models for predicting adsorption equilibrium of binary mixtures.