A mathematical model is used to predict adsorption isotherms from experimentally measured breakthrough curves. Using this approach, by performing only breakthrough experiments for a mixture of two (or more) components, one can obtain pure component adsorption isotherms up to the pressure of the experiment. As a case study, the adsorption of an equimolar mixture of CO₂ and CH₄ in zeolite ITQ-29 is investigated. Pure component linear adsorption isotherms for CO₂ and CH₄ are predicted by fitting the theoretical breakthrough curves to the experimental ones. Henry coefficients obtained from our approach are in excellent agreement with those measured experimentally. A similar procedure is applied to predict the complete Langmuir adsorption isotherm from breakthrough curves at high pressures. The resulting adsorption isotherms are in very good agreement with those measured experimentally. In our model for transient adsorption, mass transfer from the gas phase to the adsorbed phase is considered using the Linear Driving Force model and dispersion of the gas phase in the packed bed is taken into account. IAST is used to compute the equilibrium loadings for a mixture of gases. The influence of the dispersion coefficient and the effective mass transfer coefficient on the shape of breakthrough curves is investigated and discussed. Rough estimations of these values are sufficient to predict adsorption isotherms from breakthrough curves.

The influence of product shape selectivity on the bifunctional conversion of n-C₇ by zeolite catalysts is investigated. Three different zeolite catalysts with different pore sizes (MFI-type, MEL-type, and BEA-type zeolites) have been investigated experimentally. For all three catalysts, n-C₇ is isomerized to monobranched isomers which are further isomerized into dibranched isomers, and these dibranched molecules are converted into cracking products. More dibranched isomers and less cracking products are produced by BEA-type zeolite compared to MFI-type and MEL-type zeolites and clear differences are observed in the distribution of dibranched isomers produced by different catalysts. Molecular simulation is used to compute the adsorption isotherms and free energy barriers for diffusion of dibranched isomers in MFI-type, MEL-type, and BEA-type zeolites. Combining simulation results and experimental observations, it is shown that product shape selectivity can explain the distribution of dibranched molecules while transition state shape selectivity fails to do so. For the medium-pore zeolites (MFI-type and MEL-type zeolites), free energy barriers for diffusion of dibranched molecules are significant. For MFI-type and MEL-type zeolites, the dibranched molecule that has to overcome lower diffusion barrier is produced with a higher yield and the distribution of dimethylpentane molecules is determined by their diffusion rate. It is shown that there is almost no free energy barrier for the diffusion of any of these molecules in BEA-type zeolite. As BEA-type zeolite imposes no free energy barrier for diffusion of any of dibranched isomers, the distribution of dibranched isomers is very close to the equilibrium distribution in the gas phase. Due to the limited mobility of dimethylpentanes within the pores of MFI-type and MEL-type zeolites, most of the dimethylpentane molecules are trapped inside the zeolite and undergo consecutive cracking. Dimethylpentane molecules diffuse sufficiently fast in the large pores of BEA-type zeolite and transfer to the gas phase, before consecutive reaction converts these molecules into cracking products. Moreover, the effect of the MFI-type crystal size on the production of dibranched isomers is investigated. The yield of dibranched isomers reduces by increasing the size of the crystal and larger part of dibranched isomers are cracked as the crystal size of MFI-type is increased.