Adsorption Kinetic Models and Their Applications: A Critical Review

Adsorption kinetic models are essential tools to understanding the rates and mechanisms by which adsorbates interact with adsorbents. These models facilitate the prediction of pollutant removal rates and the determination of time-dependent concentrations of residual adsorbates in solutions. Commonly employed models include the pseudo-first-order and pseudo-second-order models, which are particularly effective in describing adsorption processes involving heavy metals and organic contaminants. The intraparticle diffusion model is instrumental in elucidating the diffusion mechanisms within porous adsorbents, while the Elovich model is frequently applied to systems with heterogeneous surfaces. These kinetic models have practical applications across various fields, including environmental remediation, wastewater treatment, gas storage and separation, catalysis, and the pharmaceutical and biomedical sectors. They are particularly valuable in evaluating the performance of adsorbents and investigating adsorption mass transfer mechanisms. However, challenges persist in accurately interpreting the physical meanings and solving methods of these models, especially when applied to complex real-world systems. Recent advancements have focused on developing comprehensive analytical solutions and new approaches to address these complexities, thereby enhancing the applicability and reliability of adsorption kinetic models in various applications.