Removal of Plaguicides MCPA and Imazapic from Aqueous Solution Using Carbonaceous Materials

Abstract

Two different carbonous materials have been used in this study as adsorbents for the investigation of the adsorption kinetics and isotherms of two pesticides: (MCPA and Imazapic) from aqueous solution at various pH. Two simplified kinetic models, pseudo-first-order and pseudo-second-order, were used to predict the adsorption rate constants and activation energy. Both pesticides followed pseudo-second-order kinetics on both adsorbents. The adsorption capacity of activated carbon was found to be relatively higher in acidic rather than in basic solutions for both agrochemicals. The equilibrium data were analyzed by Langmuir, Freundlich, Temkin, Sips and Guggenheim–Anderson–de Boer (GAB) isotherms in order to define the best correlation model for each pesticide on both adsorbents. MCPA adapted to Langmuir model on CAT and CARBOPAL with a R2=0.997 and 0.988, and Imazapic adapted to GAB model with R2=0.989 and 0.933, respectively.