Xylene Selectivity at the External Surface of Hierarchical Zeolites: Experiment and Molecular Modeling

Hierarchical faujasite zeolites made up of nanoparticle aggregates (NAs) and layer-like structures (LL) are evaluated for xylene adsorption in both gas liquid phases. For NA zeolites, several samples with varying external surfaces meso/macropore volumes considered. Compared to conventional faujasite, isotherms as measured by means thermogravimetric experiments display higher capacities the faujasites. This capacity increase is found be linked zeolite surface area. However, case LL zeolite, despite its large surface, comparable that zeolite. all hierarchical samples, paraxylene selectivities assessed through batch phase smaller than The observed selectivity decrease seems associated functional window adsorptive sites when enhancing surface. To shed light on phenomenon, Monte Carlo simulations Grand Canonical ensemble performed investigate a bulk infinite sample exhibiting an latter sample, chosen incomplete cavities and, therefore, defective sites. In agreement our experiments, results from molecular simulation indicate loss