Benzene Adsorption in Microporous Materials

Abstract

The adsorption behaviour of benzene in silicalite-1, AlPO 4 -5 and EU-1 has been investigated using gravimetric techniques and molecular simulation methods. For the one-dimensional, 12-membered ring (MR) channels of AlPO 4 -5 and the unidirectional, 10-MR channels with 12-MR side pockets of EU-1, the isotherms of benzene show simple type I behaviour. For the three dimensional 10-MR channels of silicalite-1, an anomalous behaviour of the benzene molecules sorbed has been observed. Two steps at loadings of ca. 4 and 6 molecules per unit cell [m.(u.c.) −1 ], respectively, and an hysteresis loop between loadings from 6 to 8 m.(u.c.) −1 can be found in the isotherms of this system. These stepped isotherms can be classified as showing type VI isotherm behaviour but in this system the reasons behind the steps are of a new and novel nature. These abnormal adsorption properties have been ascribed to the subtle interplay of increased sorbate-sorbate interactions and decreases in the entropy of sorption due to the energetically heterogeneous surfaces which are present in silicalite-1. The composition and structure of the silicalite-1 samples also play an important role on the adsorption properties of this system.

Adsorption of benzene and propene in zeolite MCM-22: a grand canonical Monte Carlo study

“…Our result is shown in Table 2, along with the simulated one by Ban et al (2007) and the experimental data by Jentys et al (2006) and Song et al (2006). We see a good agreement between our result and the others.…”

“…The experimental data of Corma et al (1996) were obtained from the calorimetric study of adsorption of toluene in MCM-22. Jentys et al (2006) and Song et al (2006) The simulated values of Hou et al (2001) and Rungsirisakun et al (2006) were those from GCMC and MD simulations, respectively. It is noted that the force field here used gives agreeable energy values to those by Corma et al (1996) and Rungsirisakun et al (2006).…”

GCMC simulations in zeolite MFI and activated carbon for benzene removal from exhaust gaseous streams

“…Figure 2 shows the comparison between our data for pure adsorption over MFI zeolite (a) and NaY zeolite (b) and, respectively, the adsorption isotherms of [19] and [39]. As expected, the agreement is fair for all the considered pressure range, bearing in mind the possible presence of impurities in the real zeolite MFI, and the slightly different Si/Al ratio (2.43 in the case of this publication).…”

Transport Phenomena in Nanoporous Materials

“…Guest-induced changes in the lattice structure have indeed been recorded experimentally by X-ray diffraction analysis, [168,169] adsorption measurements [170] and solid-state NMR [169,171] and simulated with flexible zeolite lattices, [172] referred to a re-distribution of the molecules for loadings above 4 molecules per unit cell. [173] The same phenomenon of molecular redistribution was already mentioned in Section 4.2 and is found, in both cases, to be associated with a dramatic increase in guest diffusivity. [153,167,174] Now, owing to IFM, the location of such changes can even be monitored.…”