Temperature-programmed equilibrated desorption of n-hexane as a tool for characterization of the microporous structure of zeolites

Temperature-programmed desorption (TPD) of n-hexane from the commercial ZSM-5 and Y zeolites, performed in a flow system using carrier gas saturated with n-hexane vapor, was studied by means of TG. It has been shown that the desorption is controlled by the gas–adsorbate equilibrium. The desorption profiles were fitted with the model functions based on the Langmuir adsorption model. The adsorption enthalpy and entropy values estimated as the model parameters agree with the previously reported data. Micropore volume determined from the desorption data is close to that obtained from low-temperature N2 adsorption isotherms. Application of temperature-programmed equilibrated desorption of n-hexane as a method for probing micropores in zeolites was proposed.