The sorption of nitrogen, water vapor, and benzene on a phenyl-Preliminary nitrogen sorption studies (1) suggested that the modified MCM-41 type sorbent has been studied. Nitrogen sorpmaterial prepared using 20 mol% PTES in the initial synthetion is characterized by a Type I isotherm indicating microporossis mixture was microporous. A control sample containing ity. A BET specific surface area of 882 m 2 g 01 and a Gurvitsch no phenyl groups was synthesised using 100% TEOS as the pore volume of 0.45 cm 3 g 01 were obtained. Benzene sorption also silica source. Preliminary nitrogen sorption on this control resulted in a Type I isotherm confirming the sample's microporosmaterial indicated that it was mesoporous (average pore diity. The specific surface area and total pore volume obtained from ameter ร
30 A ห) (1). We now report the investigation of the benzene isotherm are 750 { 50 m 2 g 01 and 0.31 cm 3 g 01 , the sorption of nitrogen, water, and benzene on the phenylrespectively. The discrepancy in the values obtained for the total pore volumes may be due to the structure of the adsorbed benzene. modified MCM-41 described above.
Water sorption resulted in a Type V isotherm, highlighting the hydrophobicity of the sample at low relative pressures. A capillary MATERIALS AND METHODS condensation step is evident at p/p 0 ร 0.7. Low pressure hysteresis is observed, which is attributed to rehydroxylation of the surface.