Green synthesis of iron nanoparticles (Fe(NPs)) using plant extract from Eucalyptus grandis: characterization and determination of the catalytic potential for reduction of 4-nitrophenol

Resumen

This study assessed a green synthesis method for iron nanoparticles (Fe(NPs)), using Eucalyptus grandis leaf extract, to reduce waste generation and diminish the use of conventional chemical inputs, such as Sodium Borohydride (NaBH₄), without significant losses in catalytic activity. Various volumetric ratios of plant extract and NaBH₄ were tested to understand how this variation would affect the morphological, structural, and catalytic power of the material. In the conducted analyses, a reduction in the crystallinity of Fe(NPs) was observed for proportions above 25% of the extract. However, the particle size remained stable among different syntheses, with iron ions showing improved dispersion for proportions of 40% and 50% of the extract. Regarding stabilization, characteristic bands of aromatic compounds, alcohols, ethers and carboxylic acids were identified, indicating the extract's involvement in coating the metallic cores. To assess the catalytic performance, studies were conducted on the catalytic reduction of the contaminant 4-nitrophenol to 4-aminophenol, using Fe(NPs) as catalysts. The results revealed conversions above 80% for Fe(NPs) synthesized with volumetric proportions of up to 40% of the plant extract, suggesting that substituting the chemical agent did not significantly affect the catalytic activity of the biocatalyst. Finally, ecotoxicological tests performed with Lemna minor and artemia salina demonstrated a significant reduction in the toxicity of the contaminant 4-nitrophenol, as well as the biocompatibility of the obtained Fe(NPs).

Keywords: iron oxides, stabilization, vegetable coating.