Sorption of nitrogen, water vapor, and benzene by a phenyl-modified MCM-41 sorbent

The sorption of nitrogen, water vapor, and benzene on a phenyl-modified MCM-41 type sorbent has been studied. Nitrogen sorption is characterized by a Type I isotherm indicating microporosity. A BET specific surface area of 882 m(2) g(-1) and a Gurvitsch pore volume of 0.45 cm(3) g(-1) were obtained. Benzene sorption also resulted in a Type I isotherm confirming the sample's microporosity. The specific surface area and total pore volume obtained from the benzene isotherm are 750 +/- 50 m(2) g(-1) and 0.31 cm(3) g(-1) respectively. The discrepancy in the values obtained for the total pore volumes may be due to the structure of the adsorbed benzene. Water sorption resulted in a Type V isotherm, highlighting the hydrophobicity of the sample at low relative pressures. A capillary condensation step is evident at p/p degrees approximate to 0.7. Low pressure hysteresis is observed, which is attributed to rehydroxylation of the surface. (C) 1998 Academic Press.