On the comparison of pseudo-first order and pseudo-second order rate laws in the modeling of adsorption kinetics

•In the literature about adsorption kinetics, 2 rate laws are generally compared.•They correspond to pseudo-first and pseudo-second order kinetics.•The method generally used for the comparison suffers from a methodological bias.•This bias unfairly favors pseudo-second order kinetics.•A different method is proposed to analyze experimental data.

In most works in the current literature about liquid/solid adsorption kinetics, the respective abilities of pseudo-first order and pseudo-second kinetics for describing the data are compared. In nearly all cases, it is concluded that the latter surpasses the former. The aim of this work is to point out that more caution should be exercised in this comparison. Indeed, it appears that the method generally used is flawed and that it unfairly favors pseudo-second order kinetics. A different method is proposed to analyze experimental results. It is employed here to reexamine experimental data taken from the literature.

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