Process Engineering Journal
Volume 1, Numéro 1, Pages 28-29

Common Mistake In Adsorption Papers: The Blanchard Et Al.’s Pseudo-second Order Kinetics Model Equation

Authors : Hamdaoui Oualid .


In the last decades, the removal of organic and inorganic pollutants from aqueous solutions by adsorption has been extensively investigated. The most used equations to describe and model the adsorption kinetics are the pseudo-first order and pseudo-second order models. Despite some citation inconsistencies in the literature, the pseudo-first order equation was indisputably proposed by Lagergren (Kungliga Svenska Vetenskapsakademiens Handlingar, Vol. 24, No. 4, pp. 1–39, 1898). However, the pseudo-second order model continues to be erroneously cited as the Ho’s pseudo-second order equation. This model was developed in 1984 by Blanchard et al. (Water Research, Vol. 18, No. 12, pp. 1501-1507, 1984) and only a linearized expression was proposed by Ho. Therefore, the nonlinear form of the pseudo-second order equation, which may be linearized in 6 various forms, was not originally reported and applied by Ho, but initially proposed by Blanchard et al. In a word, to be scientifically honest, the original work by Blanchard et al. should be cited for the pseudo-second order kinetics equation model.


Adsorption; Pseudo-second order equation; Blanchard et al.