The Kinetics, Mechanism and Effect of Contact Time on the Adsorption of Cadmium and Glyphosate to Alfisol

Abstract

This study was carried out using Alfisol as an adsorbent to adsorb Cadmium and Glyphosate both of which are common inorganic and organic contaminants. The soil samples were air-dried and allowed to pass through 2mm sieve before use while its analysis was done following the standard procedures. The kinetic data were tested with pseudo-first-order and pseudo-second-order models, and it was concluded that both adsorbates adsorption followed the pseudo-second-order kinetics, while the nature and the mechanism of adsorption processes were studied by using an intraparticle diffusion model. A complete linear plot of intraparticle diffusion was obtained for glyphosate which suggests that intraparticle diffusion was the rate-controlling step in its adsorption but the opposite is the case for cadmium adsorption. The peak removal of cadmium occurred after 50 minutes with equilibrium attained over 250 minutes while peak glyphosate removal was achieved after 30 minutes. It can be concluded that Alfisol can be effectively used for the adsorption of both Cadmium and Glyphosate thus showcasing a potential environmental remediation process.