Efficiency of three powdered activated carbons for the adsorption of atrazine and diuron—use of some models

The removal of atrazine and diuron, two widely used pesticides, was studied on three Powdered Activated Carbons (PAC) (kinetics and isotherms), and different adsorption models were tested: direct (saturation), Langmuir Freundlich, Adams–Bohart, Elovich, Kiselev and Fowler–Guggenheim. The results indicated that the PAC F400 from Chemviron was the best for adsorption of the two pesticides, according to its microporous structure. The Langmuir model seemed to be the best for calculating the maximal adsorption capacities and equilibrium constants. However, use of the other models showed that the adsorption was exothermic, and also realised the value of the equilibrium constant.