Abstract
Heterogeneity of adsorbent surfaces is not taken into account in models now used in the application of pulse chromatography to the measurement of kinetics and transport -properties. Heterogeneity can be allowed for by assigning sites to groups or types and adding terms to the normal model for each group. This formulation leads to a nonlinear model, and additivity means that resolution of the group parameter requires a large amount of data. A lumping model is also examined: this approach also yields a nonlineaf model, but data requirements could be less. Rate and equilibrium constants were measured for ethylene adsorption on activated alumina by pulse chromatography. Temperature-programmed desorption measurements for the same system indicated surface heterogeneity. Of the two or possibly three types of adsorption sites on the alumina surface, only the low-temperature sites participated in the pulse chromatography measurement.
