Adsorption on MCM-41 mesoporous molecular sieves. Part 2.—Cyclopentane isotherms and their temperature dependence

Abstract

The effect of temperature on adsorption isotherms of cyclopentane on mesoporous MCM-41 molecular sieves with different pore size has been determined at 243–333 K. The occurrence of adsorption hysteresis upon capillary condensation in mesopores depends on the pore critical temperature, which is lower than the bulk critical temperature and decreases with decreasing pore diameter. If the pore critical temperature is within the range of experimental temperatures of adsorption, capillary condensation on a single sieve may occur both reversibly (hypercritical region) and irreversibly (subcritical region).