ADSORPTION OF CARBON-TETRACHLORIDE AND NITROGEN BY 3.4 NM PORE DIAMETER SILICEOUS MCM-41

Adsorption isotherms of nitrogen at 77 K and carbon tetrachloride at t emperatures between 273 and 323 K have been determined on the pure sil ica form of MCM-41 of pore diameter ca. 3.4 nm. The nitrogen isotherm is of a reversible type IV in the IUPAC classification and shows a fir st-order change in the physisorption mechanism below a relative pressu re of 0.4. Carbon tetrachloride isotherms were of type V, the isotherm s at 273, 288 and 303 K showing distinctive hysteresis loops, whereas the isotherm at 323 K was completely reversible. Despite the questiona ble validity of the Kelvin equation when applied to narrow mesopores, good agreement was achieved for pore diameter calculations for all the isotherms measured.