Removal of Atrazine from contaminated water by functionalized graphene quantum dots

Abstract The limitation of clean water supplies and the increment of water pollution resources, like industrial processes, oil pollution, and herbicides, are urgent reasons for introducing new techniques for treating contaminated water. Atrazine is heavily used as a herbicide due to its high effectiveness and low price. However, its environmental persistence causes water contamination, and human exposure to Atrazine is linked to several health effects. This work presents a simulation study of the possibility of removing the Atrazine from water by functionally activated graphene quantum dots (GQDs), using density functional theory (DFT) at B3LYP/3-21G level. The activity of GQDs C46 with a total dipole moment of 0.9 is enhanced by the attachment of chemical groups; for instance, attaching CN and NO 2 groups increases the total dipole moment to 8.744 and 9.123, respectively. The effect of the functionalized groups Carboxyl and cyanide was investigated, and confirmed that there was no structure deformation due to the functionalization process. Analysis of the obtained data shows the remarkable adsorption ability of GQDs activated by CN and NO 2 groups toward the removal of atrazine herbicides due to positive adsorption energy 1.31, 128, and 1.3 eV obtained from pristine, carboxyl graphene, and cyanide graphene respectively. According to the calculated total charge on the complexes Atrazine and GQDs and Functionalized GQD, charge transfer mainly depends on the interaction pattern. The values of charges were − 0.02, 0.004, and − 0.004 for pristine, carboxyl, and cyanide graphene, respectively. Therefore, the observed results demonstrated the possibility of applying the chemically modified carbon quantum dots as a potential candidate for the treatment of contaminated water.