Performance of activated carbon and bentonite for adsorption of amoxicillin from wastewater: Mechanisms, isotherms and kinetics

Amoxicillin's traces within pharmaceutical effluents have toxic impact toward the algae and other lower organisms within food web. Adsorption, as an efficient process to remove contaminants from water was chosen; in particular with bentonite and activated carbon as adsorbents. The study was carried out at several pH values. Langmuir and Freundlich models were then employed to correlate the equilibria data on which both models equally well-fit the data. For kinetic data, pseudo-first and second order models are selected. While chemisorption is the dominant adsorption mechanism on the bentonite case, both physisorption and chemisorption play important roles for adsorption onto activated carbon. Also, several possible mechanisms for these adsorption systems were elaborated further. (C) 2009 Elsevier Ltd. All rights reserved.