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Microplastic pollution poses a growing threat to ecosystems globally, necessitating sustainable solutions. This study explores upcycling microplastics into graphene as a promising approach Traditional methods like pyrolysis and catalytic carbonization are slow and compromise graphene quality. Flash Joule heating is fast but energy‐intensive and hard to control. In contrast, atmospheric pressure microwave plasma (APMP) synthesis, the proposed technique, offers a one‐step, environmentally friendly alternative. APMP operates at relatively lower temperatures, reducing energy consumption and providing precise control over process parameters. This study demonstrates that polyethylene microplastics from waste dropper bottles can be efficiently transformed into graphene using APMP synthesis. Raman spectroscopy of synthesized material reveals a spectrum characteristic of graphene‐based materials, with indications of defects and the presence of oxygen content. X‐ray diffraction illustrates the characteristic graphitic lattice, with a slightly larger interlayer spacing attributed to intercalated functional groups. X‐ray photoelectron spectroscopy confirms sp2 hybridized carbon as the major component. High‐resolution transmission electron microscopy provides insights into the multilayered structure and variations in interlayer spacing. The as‐synthesized pristine graphene exhibits nearly ten times greater efficiency in adsorbing perfluorooctanoic acid compared to the oxidized form of graphene, although it is slightly less effective than graphene‐based nanocomposites.

The synthesis of free-standing graphene in a microwave plasma at ambient conditions is currently of great interest. The past works have relied on the usage of higher microwave powers to synthesize free-standing graphene which is not only costly but also an obstacle to the industrialization of the process. The aim of this work was to bring down the cost of the process by synthesizing graphene at a significantly lower microwave power, i.e. 250 W. The formation of graphene was confirmed through Raman spectrum and scanning electron microscopy, where the Raman spectrum showed the signature 2D peak of graphene, and the vertical orientation of the graphene was observed in the microscopic images. The application of graphene in oil-water separation is demonstrated based on its hydrophobic and oleophilic properties. The as-synthesized pristine graphene coated on a melamine sponge showed a mass absorption capacity (57 g/g) comparable to that of functionalized or composite graphene.

The adverse effects of oxalic acid (OA) on human health linked with its excessive consumption necessitates an improved sensor. Here, we demonstrate an electrochemical sensor for oxalic acid detection based on silver nanoparticles (Ag-Nps) and nitrogen-doped graphene oxide (N-GO) nanocomposite. N-GO, which was synthesized using atmospheric pressure microwave plasma has been first time employed for electrochemical application. The nanocomposite formation was confirmed through scanning electron microscopy and EDS elemental analysis. The nanocomposite-based sensor showed a higher current response, good selectivity and stability which can be attributed to the synergistic-effect of Ag-Nps and N-GO. Amperometric responses were proportional to the concentration of OA between 10 and 300 μM, and the detection limit was 2 μM.

Graphene nanostructures exhibit a wide range of remarkable properties suitable for many applications, including those in the field of biomedical engineering. In this work, plasma-enhanced chemical vapor deposition was utilized at different applied RF power for the fabrication of vertical graphene nanowalls on silicon and quartz substrates from an inherently volatile carbon precursor without the use of any catalyst. AFM confirmed the presence of very sharp exposed graphene edges, with associated high surface roughness. The hydrophobicity of the material increased with the power of deposition, reaching the water contact angle of 123 ˚ for 500 W. Confocal scanning laser microscopy demonstrated that the viability of gram-negative Escherichia coli and gram-positive Staphylococcus aureus cells were 33% and 37% when incubated on graphene samples, respectively, compared to controls (quartz) that showed the viability of 82% and 84%, respectively. SEM verified significant morphological damage to bacterial cell walls by the sharp edges of graphene walls, with cells appearing abnormal and deformed. The presented data clearly contributed to the current understanding of the mechanical-bactericidal mechanism of vertically oriented graphene nanowalls upon direct contact with microorganisms.