Adsorption of Imidacloprid on Powdered Activated Carbon and Magnetic Activated Carbon

The adsorptive characteristics of imidacloprid on magnetic activated carbon (MAC12) in comparison to powdered activated carbon (PAC) were investigated. Adsorption of imidacloprid onto powdered activated carbon and magnetic activated carbon was studied as a function of time, initial imidacloprid concentration, temperature and pH. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models for both carbons were used to describe the kinetic data. The adsorption equilibrium data were analyzed using the Langmuir and Freundlich models. For powdered activated carbon the isotherm was ‘H’ type, and ‘L’ type for magnetic activated carbon. Equilibrium data fits well to the Langmuir model in the studied concentration range of imidacloprid. It was found that both the boundary layer and intraparticle diffusion for both adsorbents play an important role in the adsorption mechanisms of imidacloprid. The adsorption of imidacloprid on PAC and MAC12 followed a pseudo-second-order kinetic model rather than pseudo-first-order model. A decrease in the adsorption of imidacloprid on powdered activated carbon and magnetic activated carbon was observed with the increase in temperature. The pH of the solutions had no effect on the adsorption capacity of the adsorbents.