Assessment of doped graphene in the removal of atrazine from water

Atrazine is a widely used toxic herbicide that poses a threat to both the environment and human health. This study investigates the removal of Atrazine from water through armchair-hexagonal hexagonal graphene quantum dots (AHEX) simulations. The investigations are performed using density functional theory at the exchange-correlation hybrid functional B3LYP/3-21G level of theory. The activity of pristine AHEX, with a total dipole moment of 0.0 (debye), is enhanced by doping with boron (B), nitrogen (N), and sulfur atoms (S), resulting in increased total dipole moments of 8.99, 5.29, and 4.14 Debye respectively. This enhancement occurs without any structural deformation due to the doping process. Our results show significant adsorption capacity of the doped nanographene for Atrazine, evidenced by the high adsorption energies of 0.52 eV for boron, 0.62 eV for nitrogen, and 2.97 eV for sulfur. Charge distribution on the atrazine complexes further confirms effective interaction, with values of 0.03, - 0.018, and 0.032 (e). UV-vis spectroscopy reveals that the prominent absorption peaks of boron and nitrogen-doped samples, initially at ~ 658.8 and 431 nm, undergo a redshift to ~ 676 and 444.3 nm after adsorption, respectively. This redshift aligns with the dominant excitation moving to lower energies following adsorption. Conversely, the sulfurated nanographene shows a blue shift from 980.66 to 485.41 nm. These findings highlight the potential of doped nanographene as an effective treatment for atrazine-contaminated water.