Humans, animals and wildlife can suffer consequences due to exposure to toxic substances present in the environment, such as disinfection by-products, the halo benzoquinones, which are formed through reactions between chlorine and natural organic matter present in the water. In this paper, the interaction of 2,6-dichloro-3-methyl-1,4-benzoquinone with graphene layer was investigated by ab initio methods based on the density functional theory. The results show that 2,6-dichloro-3-methyl-1,4-benzoquinone adsorption changes the electronic properties of the nanostructure depending on molecule adsorption site. The calculated binding energies show that this molecule interacts with graphene through a chemical adsorption process when the 2,6-dichloro-3-methyl-1,4-benzoquinone molecule is parallel to the graphene layer. Our results are promising because they indicate the ability of graphene to serve as a filter for toxic substances present in the water.

In this work, a systematic study of 17α-ethinylestradiol and estrone molecules interacting with single wall carbon nanotube is presented by means of first principle calculations. The structural properties, binding energy, charge transfer, and electronic properties were calculated and analyzed to characterize the effect of interaction of 17α-ethinylestradiol and estrone molecules on the nanotube surface. Results show that the molecular structure and electronic character of single wall carbon nanotube were not affected due to the presence of the molecules. It is observed via binding energy calculated that ethinylestradiol and estrone molecules interact weakly with the nanotube. The results are very interesting once that they suggest that nanotubes are sensitive to 17α-ethinylestradiol and estrone molecules which can lead to confection of sensor to detect these molecules.