Mathematical models of the adsorption-desorption kinetics of fenitrothion in clay soil and sandy clay loam soil

Abstract

Batch adsorption and desorption kinetic experiments of fenitrothion on clay soil and sandy clay loam soil indicated that the equilibration time was approximately 30 hours. The kinetics of adsorption and desorption exhibited two distinct stages: a rapid process in the initial stages followed by a slow process. The pseudo-first-order model followed by the Elovich kinetic model fit the experimental adsorption and desorption data quite well, with high values of R2 and low values of ∆qe% and SSE. Accordingly, the pseudo-first-order model is most suitable for describing the adsorption and desorption kinetics of fenitrothion on clay soil and sandy clay soil. Pseudo-second-order model type-1 and type-2 models fit the experimental adsorption data; however, these models cannot be used to describe desorption kinetics. Moreover, the modified Freundlich model has limited applicability, and the intraparticle diffusion kinetic model cannot describe the kinetics of the adsorption and desorption of fenitrothion on clay and sandy clay loam soils.