Computing Adsorption Isotherms for Benzene, Toluene, and p-Xylene in Heulandite Zeolite

Abstract

When computer simulations were performed in the grand canonical ensemble, adsorption isotherms for benzene, toluene, and p-xylene in Heulandite zeolite were constructed. Nitrogen adsorption was simulated to test a feasible computational strategy. Simulations were performed at three temperatures (200, 298, and 473 K), at pressures ranging from 0 to 200 kPa, and at water contents ranging from 0% to 4%. It was found that the adsorption of the organic species was not significantly affected by increasing the pressure over 10 kPa. Also, increasing the water content of the zeolite reduced the adsorption of these aromatics significantly. On the other hand, as the temperature was increased the amount of adsorbed material was only slightly affected. To access adsorption selectivity information, various mixtures of the aromatics were studied. Results from the simulations show that adsorption of benzene was higher than that of toluene, and toluene adsorption was higher than that of p-xylene. A relation between the electronic environment of the molecular species and the amount of adsorbed material was established. The results obtained are compared with experimental data available on other synthetic and natural zeolites.

Separation and isomerization of xylenes using zeolite membranes: a short overview

“…cage‐like or channel‐like) and pore size (see for instance Refs. 74–82). At lower temperatures, however, the isotherms of benzene, toluene and p ‐xylene on MFI display increased capacities with a step or inflection point at about four molecules/unit cell83–85 (Fig.…”

New adsorbents for purification: Selective removal of aromatics

“…Watanabe et al, 1995 . Adsorption of benzene on NaY, Heulandite, and MFI-type zeolites has also been studied ŽSnurr et al, 1994;Kitagawa et al, 1996;Klemm et al, 1998; . Laboy et al, 1999 . However, these studies did not involve the effects of -complexation on adsorption.…”

Adsorption of C6–C8Aromatics over Ba‐Exchanged Zeolite X at High Temperature

“…Song et al [30] reported that the presence of mesopores in zeolite beta provides more space for adsorption and increases the adsorption capacity. Laboy et al [29] studied the adsorption of Bz, TOL, and PX in heulandite, with the increase of the water content from 0 to 4 %; the adsorption decreased significantly. Since a dry zeolite was used in this study, a larger space inside the adsorbent may be available for adsorption, which can lead to higher adsorption quantity.…”