Influence of KIT-6's pore structure on its surface properties evaluated by inverse gas chromatography

The pore structure of mesoporous silica KIT-6 has been systematically tuned via the variation of calcination temperature (773-1223 K), with the mesopore size ranging from 4,8 to 7.5 nm and micropore volume from 0.000 to 0.078 cm(3)/g, respectively. Four n-alkanes (C6-C9), cyclohexane, benzene, toluene, trichloroethylene, and tetrachloroethylene were employed as probe molecules in the evaluation of the pore structure effect on KIT-6 surface property using inverse gas chromatography (463.2-493.2 K). High free energy of adsorption and enthalpy of adsorption were observed on the KIT-6 with the micropore volumes. The dispersive interaction parameter gamma(D)(S), and specific interaction parameter I-SP, were found to decrease with the increment of the mesopore size of the samples. These results indicate that the occurrence of micropore contributes the adsorption, while the narrow mesopore of KIT-6 promotes the dispersive and specific interaction. (C) 2012 Elsevier B.V. All rights reserved.