A New Method for the Determination of Low Coverage Adsorption Heats for Zeolite-VOC Systems

摘要

In this paper,we present a new experimental technique and a mathematical procedure for the calculation of the isosteric heats of adsorption of VOC-zeolite systems.This procedure provides a continuous isosteric heat curve over a large coverage ratio range including the low-coverage area.Results are given for a toluene-NaY system at 423 K.The validity of the method is discussed by comparison with other methods.The fundamental understanding of the adsorption of VOC compounds in the porous structure of zeolite adsorbents is of prime importance for the design of tailor-made adsorbents in the field of purification of VOC-loaded waste gases by adsorption process.For this purpose,the isosteric heat of adsorption extrapolated to the limit of zero coverage is interesting as it governs the dependence of the Henry constant with the temperature.It is also directly related to the interactions between the adsorbed molecules and the atoms of the zeolitic structure.