Kinetic and Thermodynamic study for Adsorption a Desorption of Diazinon with copper in the presence of Surfactant
In the present work change in the adsorption-desorption processes of Diazinon[O,Odiethylo-( 2-isopropyl-6-methyl4pyrimidinyl) phosphorothioate] which is nonionicorganophosphorous pesticide, preformed by using batch equilibrium experiments on six agricultural soil samples. The kinetics study for adsorption processes investigated that first order rate law and power function equation model provided the best correlation with experiment results. The isothermal models Linear, Freundlich, and Langmuir were applied to describe the adsorption-desorption affinities to the soils. Thermodynamic parameters (ΔG, ΔH and ΔS) were also calculated according to the values of binding Langmuir constant KL at 10, 25, 40 ±1ºC. Linear coefficient Kd values for adsorption process of diazinon varied between 3.261 – 6.413 mlg- 1. Freundlich coefficient KF values for adsorption process varied between 1.194 – 1.506 mlg-1. Langmuir coefficient KL for adsorption process varied between 0.017 – 0.020 mlg-1. The negative values for each of ΔG, ΔH and ΔS constants confirmed that diazinon adsorption processes more at lower temperature and done via enthalpy effect.
