Comments on “Elimination of Bisphenol A from Water <em>via</em> Graphene Oxide Adsorption”

Xu and Zhu published the paper entitled“Elimination of Bisphenol A from Water via Graphene Oxide Adsorption”. In section of 3.2 BPA adsorption kinetics, authors stated that “The pseudo-first- order model”and cited Blanchard et al. to be a reference. There is nothing about the pseudo- first- order model in the reference. It is a quotation error. The Lagergren rate equation presented in 1898, is a first order model. Basically, the rate of a reaction is defined as the change in concentration of a reactant or product per unit time. Concentrations of products do not appear in the rate law because the reaction rate is studied under conditions where the reverse reactions do not contribute to the overall rate. The reaction order and rate constant must be determined by experiments. In order to distinguish the kinetic equation based on the concentration of a solution from the adsorption capacity of solids, this Lagergren first order rate equation has been called a pseudo-first-order one. In addition, regression of pseudo-first-order kinetic model in Fig.1 would not be possible.