Elovich equation deviations from

Thus, including the lateral interactions between adsorbed molecules does not change the analytical form of the Elovich equation but does change the parameters of the equation. Deviations from the Elovich equation at higher surface coverages cannot, therefore, be attributed to lateral interactions between adsorbed molecules. Apart from peculiarities of some adsorption systems, the most probable source of these deviations may therefore be the neglect of the simultaneous desorption rate, i.e., the term Rj in Eq. (4). 

Surface heterogeneity has ever been considered to play a major role on adsorption [desorption] kinetics on [from] real surfaces and on heterogeneous catalytic processes. In fact, the most frequently observed kinetics which deviate from the theoretical first- or second-order ones, i.e. the time-logarithm law commonly known as Elovich equation, have in most cases been interpreted as due to surface heterogeneity. 

That equation and its integral form soon gained enormous popularity among scientists investigating the kinetics of gas adsorption on solid surfaces. Correlations of experimental data usually started with the application of that equation, and the frequently noted deviations from "Elovich behavior" were the form of analysis in dozens of published papers. Even reviews followed that general trend, discussing the Elovich equations and "deviations" from it. 

A neglect of desorption kinetics may be the source of the deviations from the Elovich behavior" observed in real adsorption systems. The new theoretical approach based on SRTIT also allows us to develop in a easy way a more general form of the Elovich equation, taking into account desorption kinetics. The form thus derived can now be tested against previously deviant adsorption kinetics data. 

In addition to the above-mentioned common deviations from the Elovich equation at very low surface coverages, the other common negative deviation was observed at higher coverages. T o account for that negative deviation, Higuchi et al. [64] proposed the following modification of Eq. (I) ... 

Other possible reasons for the deviations at higher surface coverages have also been put forward. From our derivation of the Elovich equation it follows that the main reason may be the neglect of the desorption kinetics inherent in the form of the Elovich equation. Moreover, there is the role of the lateral interactions between the adsorbed molecules. 

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