Heavy metals are inorganic contaminants derived from natural and anthropogenic sources that cause damage to ecosystems. Various environmental technologies, both chemical and biological, have been used to remediate soils impacted by these pollutants. Currently the use of nanotechnology through carbon nanomaterials has attracted attention for its ability to immobilize heavy metals in soil. The objective of this review was to explore the potential of carbon-based nanomaterials as an innovative technology for the remediation of soils contaminated with heavy metals. In this review, we used major scientific databases as our source of scientific literature and selected recent articles on heavy metals, soil remediation, carbon nanomaterials, and their applications in nanoremediation. We found that heavy metals are toxic to soil microorganisms and plants, can damage metabolic processes, leading to cell death. These contaminants can easily enter the food chain through food produced in agricultural fields, posing a risk to human health. We have found that carbon-based nanomaterials can immobilize and reduce the translocation of heavy metals and have potential as remediators of soil contamination. Furthermore, based on available data, there are few scientific reports on the use of carbon-based nanomaterials for the remediation of heavy metal soils. While every environmental technology for the remediation of soils contaminated with heavy metals has its advantages and disadvantages, the development of carbon nanomaterials offers a novel alternative as a control and remediation measure for heavy metals that has a great future in environmental protection.

In this work, we report a green synthesis of zinc oxide (ZnO) nanoparticles using aqueous and ethanolic extracts of Tradescantia spathacea (purple maguey) as bioreducing and stabilizing agents, which are plant extracts not previously employed for metal oxide nanoparticle synthesis. This method provides an efficient, eco-friendly, and reproducible route to obtain ZnO nanoparticles, while minimizing environmental impact compared to conventional chemical approaches. The extracts were prepared following a standardized protocol, and their phytochemical profiles, including total phenolics, flavonoids, and antioxidant capacity, were quantified via UV-Vis spectroscopy to confirm their reducing potential. ZnO nanoparticles were synthesized using zinc acetate dihydrate as a precursor, with variations in pH and precursor concentration in both aqueous and ethanolic media. UV-Vis spectroscopy confirmed nanoparticle formation, while X-ray diffraction (XRD) revealed a hexagonal wurtzite structure with preferential (101) orientation and lattice parameters a = b = 3.244 Å, c = 5.197 Å. Scanning electron microscopy (SEM) showed agglomerated morphologies, and Fourier transform infrared spectroscopy (FTIR) confirmed the presence of phytochemicals such as quercetin, kaempferol, saponins, and terpenes, along with Zn–O bonding, indicating surface functionalization. Zeta potential measurements showed improved dispersion under alkaline conditions, particularly with ethanolic extracts. This study presents a sustainable synthesis strategy with tunable parameters, highlighting the critical influence of precursor concentration and solvent environment on ZnO nanoparticle formation. Notably, aqueous extracts promote ZnO synthesis at low precursor concentrations, while alkaline conditions are essential when using ethanolic extracts. Compared to other green synthesis methods, this strategy offers control and reproducibility and employs a non-toxic, underexplored plant source rich in phytochemicals, potentially enhancing the crystallinity, surface functionality, and application potential of the resulting ZnO nanoparticles. These materials show promise for applications in photocatalysis, in antimicrobial coatings, in UV-blocking formulations, and as functional additives in optoelectronic and environmental remediation technologies.