A new adsorption isotherm for heterogeneous adsorbent based on the isosteric heat as a function of loading

✍ Scribed by D.D. Do; Ha D. Do

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 1012 KB
• Volume: 52
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/s0009-2509(96)00418-6

✦ Synopsis

A new adsorption isotherm model is proposed in this paper for a heterogeneous solid. The basis of this isotherm equation is that the degree of heterogeneity is reflected through the variation of the isosteric heat of adsorption with respect to loading. This degree as well as the pattern of heterogeneity is assumed to be independent of adsorbate used. The influence of the adsorbate on the isotherm will be through the interaction energy at zero loading as well as parameters which reflect the way in which the adsorbate fits into the adsorption sites. The resulting isotherm equation is very general, and under certain conditions it reduces to many isotherms commonly used in the literature, such as the Langmuir, Langmuir-Freundlich, Toth, Fowler-Guggenheim and Nitta et al. equations. The new isotherm is tested with adsorption isotherm data of many adsorbates on various samples of activated carbon and zeolite, and the parameters extracted for these adsorbates shed some light on the system heterogeneity.