▎ 摘　　要

The chemical functionalization of graphene oxide nanosheets (GO) with aliphatic amino acids such as arginine and lysine (Arg and Lys), was studied to determine the zwitterionic behavior of nanomaterials under specific pH conditions (Arg at pH 8 and Lys at pH 9.8). For this purpose, the primary amine of each amino acid was previously activated, aiming to promote the formation of C-N bonds between the amino acid and the epoxide groups at the surface of GO nanosheets. Results showed significant changes in the crystalline structure and morphology of GO with this amino acid incorporation, associated with C-N bond formation and, corroborated by FTIR and XPS measurements. Consequently, Zeta potential of the functionalized graphene oxide nanosheets presented an isoelectric point ca. 2.14 for GO-Arg and 2.41 for GO-Lys, suggesting a zwitterionic behavior in aqueous solutions. Zwitterionic behavior of GO nanosheets decorated with aliphatic amino acids may act as a selective nanomaterial for organic dye removal.