Further examination of the relationship between the Langmuir kinetics and the Lagergren and the second-order rate models of batch adsorption

• The relationship between Langmuir kinetics and the Lagergren and the pseudo-second order rate models is examined.
• A rational treatment of earlier works attempting to connect Langmuir kinetics to simple rate models is provided.
• Corrected relationships between for the first and second order models are shown and their significance discussed.

This study presents a further examination of the relationship between the Langmuir kinetics and the Lagergren (first-order) and the second-order rate models of batch adsorption. The earlier work of Liu and Shen on the transformation of the Langmuir kinetic equation to a linear combination of the Lagergren rate expression and the second-order rate expression was given a rational treatment and solutions of the transformed equation were obtained. Based on the solutions, correct relationships between the Langmuir equation and the first-order and second-order equations were established and the significance of the relationships discussed.

Adsorption kinetics modeled by Langmuir kinetics, in scaled coordinates, for different values of rate constants.Figure optionsDownload as PowerPoint slide