(219a) Isosteric Heats of Adsorption of Water on Zeolites

In adsorption based technologies, it is vital to consider the heat released by the adsorption process, because it will influence the overall process in terms of the cost of energy that is required to control column temperature, a change in adsorption equilibrium to lower adsorption capacity and the energy cost of desorption during adsorbent regeneration.

The heat evolved by adsorption can be described as a differential heat of adsorption which is defined in thermodynamics models as the isosteric heat q_st, which is the heat released by the transfer of gas at fixed adsorbate loading at a certain temperature and pressure [1,2]. The isosteric heat of adsorption can be obtained from adsorption isotherms measured in a narrow temperature rage via Clausius-Clapeyron equation. In present study we want to highlight Gravimetric Dynamic Vacuum Vapor Sorption Analyzer (DVS Vacuum) that is employed to measure water adsorption/desorption isotherms in a broad temperature range in order to calculate the isosteric heat of asdorption.