Green and cost-effective synthesis of 2D and 3D graphene-based nanomaterials from Drepanostachyum falcatum for bio-imaging and water purification applications

Herewith, we demonstrate a novel top-down approach for the cost-effective consecutive synthesis of 2D/3D graphene-based materials (GBM) from the extract and fibrous parts of the Drepanostachyum falcatum plant, using a two-stage thermal approach. At low temperature (150 degrees C), the extract of the D. falcatum showed the formation of a fluorescent 2D skeleton of the GBM i.e., metal-doped graphene oxide sheets (MDGOs) in presence of ethanol. On the other hand, the pyrolysis (similar to 300 degrees C) of the fibrous part showed the formation of a 3D skeleton of the graphene nanoribbons (GNR) in the N-2 atmosphere. The presence of extensive pi-pi conjugated interactions with oxidative functional moieties in 2D-MDGOs is responsible for their blue fluorescent nature under UV irradiation at 365 nm. Meanwhile, 2D-MDGOs show excellent potential as a bio-imaging probe for non-tumorigenic prostate epithelial RWPE-1 cells. However, the very low cytotoxicity of 2D-MDGOs played a crucial role in upholding their bio-imaging potential. Simultaneously, the hydrophobic nature of 3D-GNR showed better adsorption towards the organic pollutants (dye) from the aqueous phase. The adsorption phenomenon of 3D-GNR was very fast and effective towards the removal of methylene blue (MB). Moreover, the Langmuir adsorption capacity for MB dye was found to be 31.94 mg/gm. This is the first time we are reporting the dual synthesis of 2D and 3D GBMs simultaneously, with different applicative potentials. Further, noticeable and in-depth observations were made for studying the reaction kinetics of the reaction to find a formal analytical connection between productivity, adsorptive, and applicability of 3D-GNR. Moreover, the market-based-cost analysis showed the huge industrial potential of these materials, which also make them inevitable and promising candidates for futuristic growth in their respective application in water purification.

Automated summary

In this study, a novel method was demonstrated to synthesize 2D/3D graphene-based materials from the extract and fibrous parts of the Drepanostachyum falcatum plant. The materials obtained through different thermal approaches showed fluorescent properties and excellent adsorption capacity.