Síntese fito-assistida de nanopartículas de prata utilizando extrato folhar de capim-Annoni (Eragrostis plana Nees) e sua aplicação para redução catalítica de corantes tóxicos

Abstract

In the current work, we presented the first report on the use of capim-annoni, (Eragrostis plana Nees), an abundant, non-toxic, and renewable Brazilian biomass for green synthesis of silver nanoparticles. The phytosynthesis of silver nanoparticles (AgNPs) was carried via one-step route using the aqueous extract of CA and silver nitrate (AgNO3) as a precursor. The authenticity of phytosynthesized AgNPs was confirmed by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR ATR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The UV-Vis spectroscopy analysis showed characteristic surface plasmon resonance (SPR) absorption peak with max centered at 410 nm, confirming the satisfactory formation of AgNPs. The phyto-synthesized AgNPs were stable over for four months. FTIR-ATR analysis confirmed the existence of water soluble biomolecules in EpN leaves extract content by chemical groups such as -OH, -NH, -CO, -COC, and -OHCO can be involved in reduction, capping, and stabilization of AgNPs. XRD measurements confirmed the polycrystalline phase of AgNPs. TEM analysis confirmed that the AgNPs were quasi-spherical, with particle diameters ranging from about 10 to 40 nm and an average particle size distribution of (23.06 ± 4.0) nm. AgNPs exhibits excellent catalytic activity in the reduction of Crystal violet (CV) and Toluidine blue (AT) dyes, both highly polluting organic compounds. The reduction of CV and AT with AgNPs in the presence of NaBH4 at room temperature, occurred with just 3 min and 5 min of reaction, respectively. The rate constant (k) values were calculated to be 0.3560 min -1 for CV and 0.2977 min-1 for AT.