Analysis of global and sequential mass transfers for the adsorption of atrazine and simazine onto granular activated carbons from a hydrodynamic column

Abstract

The presence of micropollutants, particularly herbicides, in drinking water is undesired and therefore removal is required. Granular activated carbon (GAC) is used extensively to remove organic micropollutants during the treatment of potable waters. The performance of an adsorption-based separation depends on the existence of a force field at the surface of a solid. To date, the resistance of mass transfer for the adsorption of micropollutants from aqueous solution onto GAC still needs to be verified. This paper uses the developed mathematical models to analyse the global and sequential mass transfers for the adsorption of atrazine and simazine onto different GACs from a hydrodynamic column. The resistance of mass transfer is dependent on the porous diffusion before a 5% outflow occurred and both on the porous diffusion and film mass transfer after passing that percentage of outflow. The properties of adsorbate and adsorbent affecting the global, external and internal mass transfer are analysed to contribute to the investigation of adsorption mechanisms. The mechanisms of adsorption of atrazine and simazine onto GACs from the hydrodynamic column are verified.