Temperature programmed desorption of toluene, p-xylene, mesitylene and naphthalene on Na–AlSi–MCM-41 and H–AlSi–MCM-41

Adsorption properties of the mesoporous H–AlSi–MCM-41 and Na–AlSi–MCM-41 materials for aromatic hydrocarbons have been investigated by studying the temperature programmed desorption (TPD) of toluene, p-xylene, mesitylene and naphthalene over the mesoporous materials from 323 to 673 K at different linear heating rates (5–25 K min−1). The toluene TPD spectra show three distinct peaks for the H–AlSi–MCM-41 but a single asymmetric peak with humps for the Na–AlSi–MCM-41. The TPD spectra of all the other aromatic hydrocarbons for both the adsorbents show a single asymmetric peak with humps. The order of the heat of adsorption for the aromatic hydrocarbons, estimated from the temperature dependence of their peak (first one) maximum temperature was found as follows: toluene