Characterization of Iron–Polyphenol Nanoparticles Synthesized by Three Plant Extracts and Their Fenton Oxidation of Azo Dye

Abstract

In this paper, iron−polyphenol nanoparticles (Fe−P NPs) were synthesized using the extracts obtained from Australian native plant leaves, these being Eucalyptus tereticornis, Melaleuca nesophila, and Rosemarinus officinalis. The Fe−P NPs synthesized from the extracts were characterized using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results show that the reaction between iron ions and polyphenols can form complex nanoparticles with sizes ranging from 50 to 80 nm, the surface of which presents organic characters. The synthesized nanoparticles were then utilized as a Fenton-like catalyst for decolorization of acid black 194 in solution. The batch experiments showed that 100% of acid black was decolorized, and over 87% total organic carbon (TOC) was removed. In addition, removal of acid black 194 fitted well to the pseudo-first-order model. Compared with the conventional Fenton reaction, the Fenton-like reaction with Fe−P NPs takes place more sustained and carefully within 200 min. Furthermore, it does not need to adjust pH for the reaction.

Yerba Mate Tea Extract: a Green Approach for the Synthesis of Silica Supported Iron Nanoparticles for Dye Degradation

“…The non-supported YM Fe presented large peaks around 25 and 43°, which was also observed in the supported catalysts and could be due to iron materials of very poor crystallinity or to organic matter. 23 This behavior was also reported by other groups; iron nanoparticles prepared by green tea extract were deficient at the peak of Fe 0 and the authors attributed it to their amorphous nature as the iron surface is capped and stabilized by the polyphenols. 21,26,31 Other authors have also reported a complete amorphous sample, for instance, iron nanoparticles prepared using Australian native plants as Eucalyptus tereticornis, Melaleuca nesophila and Rosemarinus officinalis.…”

“…21,26,31 Other authors have also reported a complete amorphous sample, for instance, iron nanoparticles prepared using Australian native plants as Eucalyptus tereticornis, Melaleuca nesophila and Rosemarinus officinalis. 23 However, for other catalysts, peaks of iron oxides were observed, which did not appear in our case. 32,33 It is important to point out that the catalyst prepared under argon atmosphere, YM4 Figure 2 shows SEM micrographs of the Fe/SiO 2 catalysts synthesized by NaBH 4 , the morphology is similar to the free iron(0) nanoparticles ( Figure S2).…”

“…50% The tea extract was prepared from 25 g of toasted yerba mate tea in 100 mL of water at 80 o C for 1 h. Leaves were filtered off at reduced pressure and let to cool down to room temperature. 23,28 The total polyphenol concentration (TPCo) of the extract, 0.5373 g GA L …”

“…20 Green iron nanoparticles prepared in presence of green tea (Camellia sinensis) have been successfully applied in the degradation of malachite green 21 and bromothymol, 22 and similar catalysts prepared in presence of Australian native plants were able to degrade acid black 194. 23 However, most of the green nanoparticles reports addresses the preparation of non-supported catalysts, which form residual iron slush and prevents the catalyst recyclability, with the exception of the iron nanoparticles supported on clay successfully applied in the removal of arsenic(III). 24 More detailed characterization of iron nanoparticles synthesized using green tea revealed the progressive reduction of Fe 3+ to Fe 2+ during the preparation to form nanoparticles of amorphous nature, while the nanoparticles prepared by the borohydride reduction method were identified as crystalline zero-valent iron nanoparticles.…”

Plant-Mediated Green Synthesis of Iron Nanoparticles

“…Leaves of three plants native to Australia, namely, Eucalyptus tereticornis (A), Melaleuca nesophila (B), and Rosmarinus officinalis (C) were explored by Wang et al [35] for their efficiency in synthesizing iron nanoparticles and used as heterogeneous Fenton-like catalyst for decolourization of azo dye (Acid black 194) and total organic carbon (TOC). Fe-P NPs A showed maximum removal capacity of dye followed by Fe-P NPs B and Fe-P NPs C, depending on the size of the nanoparticles synthesized.…”