Atrazine adsorption by graphene-based materials: Interaction mechanism and application in real samples

The wide use of atrazine (ATZ) as a triazine herbicide poses serious threats to the environment and human health. Therefore, it is particularly necessary to develop some effective methods for the removal of ATZ from the environment. Here, we studied the removal of ATZ from aqueous solutions by three graphene-based materials (GBMs), in-cluding graphene oxide (GO), reduced graphene oxide (rGO) and graphene nanoplatelets (GNP). The results revealed that all the three GBMs had extremely high ATZ adsorption capacity, which followed the order of rGO (1083.94 mg/g) > GO (1011.94 mg/g) > GNP (1005.77 mg/g), and they were also confirmed to be applicable to actual samples. The adsorption was well fitted by the Elovich kinetic model with the determination coefficient (R2) > 0.985, 0.998 and 0.993 for GO, rGO and GNP, respectively. Moreover, the adsorption isotherm data were fitted to the Langmuir, Freundlich, Temkin, Dubinin- Radushkevich and Sips models. The results revealed that the adsorption process was the best fit by the Sips model. The fitting results of adsorption kinetics and adsorption isotherm demonstrated that the adsorption is a multi-mechanism process. In addition, the interaction mechanism of ATZ with the adsorbents was investigated by density functional theory (DFT), and the visual illustration revealed that the adsorption process was driven synergistically by H-bonding and pi - pi conjugation interactions. The developed materials are of high convenience and feasibility, and have great application potential in the removal of ATZ and other pesticides from the aqueous environment. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).