GRAPHENE-BASED 3D NANOMATERIALS DECORATED WITH SILVER NANOPARTICLES

Resumo

Environmental pollution of water is enhanced when it presents contaminants that are not removed from water through the conventional treatment system, such as emerging contaminants, pesticides, organic contaminants, and dyes. Remove these pollutants from water requires efficient materials; an example is three-dimensional (3D) graphene which has a large specific surface area, excellent mechanical properties, and versatile surface chemistry, all of which give the material a high performance for environmental applications such as adsorption and removal of pollutants from water. The addition of metallic nanoparticles in the graphene 3D structure makes this material have specific properties, such as higher electrical conductivity and antimicrobial activity. Besides, the method of preparation (reagents amount and order of addition) of these materials influence their structure, morphology, and properties. Thus, this work aimed to synthesize and characterize graphene-based 3D nanomaterials and silver nanoparticles. The synthesis of these materials was performed using a thermochemical route, were simultaneously we reduced the graphene oxide and decorated with silver nanoparticles and microparticles. The effects of the silver concentrations, surfactant addition presence, order, and time of reagents addition were evaluated. The materials were characterized by scanning electron microscopy (SEM), Raman spectroscopy, and infrared spectroscopy (FTIR). Theoretical, computational simulation studies are being conducted to justify the preferential location of nanoparticles in graphene sheets. The synthesis methodology used provided the formation of a well-defined three-dimensional structure with the presence of pores. Variations in the amount of silver, presence or absence of surfactant, order, and time of reagent addition promoted significant changes in morphology, and spectroscopy data also show the occurrence of significant structural changes. It has been observed that the presence of a surfactant helps in the formation of a massive amount of silver nanoparticles, preventing their agglomeration. Through SEM, it was possible to observe that the presence of nanoparticles and microparticles occurs preferentially in the edges and wrinkles of the graphene sheets. Silver nanoparticles and microparticles have a majority spherical shape, but also silver cubes and needles shapes. These results demonstrate that synthesized materials have ideal features for environmental applications, such as water pollutant removal and degradation, antimicrobial properties, and use as analytical sensors.