Adsorption of carbon tetrachloride and nitrogen by 3.4 nm pore diameter siliceous MCM-41

Abstract

Adsorption isotherms of nitrogen at 77 K and carbon tetrachloride at temperatures between 273 and 323 K have been determined on the pure silica 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 first-order change in the physisorption mechanism below a relative pressure of 0.4. Carbon tetrachloride isotherms were of type V, the isotherms at 273, 288 and 303 K showing distinctive hysteresis loops, whereas the isotherm at 323 K was completely reversible. Despite the questionable validity of the Kelvin equation when applied to narrow mesopores, good agreement was achieved for pore diameter calculations for all the isotherms measured.