Heats of adsorption from liquid solutions and from pure vapor phase: Adsorption of thiophenic compounds on NaY and 13X zeolites

A study of adsorption of thiophenic sulfur compounds, thiophene (T), benzothiopnene (BT), and dibenzothiophene (DBT), in normal alkane solvents (ç-octane and hexadecane) on NaY and 13X zeolites was performed. Adsorption isotherms of pure-component ç-octane, hexadecane, and T from the vapor phase were also measured. Analysis of the heats of adsorption (including differential and integral heats) calculated by using the Clausius-Clapeyron equation were in agreement with the results obtained by Ng et al. using flow calorimetry for the same systems. The simple theory estimating the relationship between the heat of adsorption from liquid solution and that from the vapor phase proposed in our previous work was tested using the experimental data. The enthalpies of solvation for T-octane and T-hexadecane were also used to validate the simple theory. The theoretical predictions were in close agreement with experiments. The simple theory is easy to use and can explain and provide insight into adsorption from liquid solution.