Mechanisms of green synthesis of iron nanoparticles using Trifolium alexandrinum extract and degradation of methylene blue

Elucidating the structural, catalytic, and antibacterial traits of Ficus carica and Azadirachta indica leaf extract-mediated synthesis of the Ag/CuO/rGO nanocomposite

The present exploration demonstrates the efficient, sustainable, cost-effective, and environment-friendly green approach for the synthesis of silver (Ag)-doped copper oxide (CuO) embedded with reduced graphene oxide (rGO) nanocomposite using the green one-pot method and the green deposition method. Leaf extracts of Ficus carica and Azadirachta indica were used for both methods as reducing and capping agents. The effect of methodology and plant extract was analyzed through different characterization techniques such as UV-visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM). The lowest band gap of 3.0 eV was observed for the Ag/CuO/rGO prepared by the green one-pot method using F. carica. The reduction of graphene oxide (GO) and the formation of metal oxide was confirmed through functional group detection using FT-IR. Calculation of thermodynamic parameters showed that all reactions involved were nonspontaneous and endothermic which shows the stability of nanocomposites. XRD studies revealed the crystallinity, phase purity and small average crystallite size of 32.67 nm. SEM images disclosed that the morphology of the nanocomposites was spherical with agglomeration and rough texture. The particle size of the nanocomposites calculated through HRTEM was found in agreement with the XRD results. The numerous properties of the synthesized nanocomposites enhanced their potential against the degradation of methylene blue, rhodamine B, and ciprofloxacin. The highest percentage degradation of Ag/CuO/rGO was found to be 97%, synthesized using the green one-pot method with F. carica against ciprofloxacin, which might be due to the lowest band gap, delayed electron-hole pair recombination, and large surface area available. The nanocomposites were also tested against the Gram-positive and Gram-negative bacteria. RESEARCH HIGHLIGHTS: Facile synthesis of Ag/CuO/rGO nanocomposite using a green one-pot method and the green deposition method. The lowest band gap of 3.0 eV was observed for nanocomposite prepared by a green one-pot method using Ficus carica. Least average crystallite size of 32.67 nm was found for nanocomposite prepared by a green one-pot method using F. carica. Highest antibacterial and catalytic activity (97%) was obtained against ciprofloxacin with nanocomposite prepared through green one-pot method using F. carica. A mechanism of green synthesis is proposed.

Green synthesis of SiO2 nanoparticles from Rhus coriaria L. extract: Comparison with chemically synthesized SiO2 nanoparticles

The usage of the green synthesis method to produce nanoparticles (NPs) has received great acceptance among the scientific community in recent years. This, perhaps, is owing to its eco-friendliness and the utilization of non-toxic materials during the synthesizing process. The green synthesis approach also supplies a reducing and a capping agent, which increases the stability of the NPs through the available phytochemicals in the plant extractions. The present study describes a green synthesis method to produce nano-silica (SiO₂) NPs utilizing Rhus coriaria L. extract and sodium metasilicate (Na₂SiO₃.5H₂O) under reflux conditions. Sodium hydroxide (NaOH) is added to the mixture to control the pH of the solution. Then, the obtained NPs have been compared with the chemically synthesized SiO₂ NPs. The structure, thermal, and morphological properties of the SiO₂ NPs, both green synthesized and chemically synthesized, were characterized using Fourier-transform infrared spectroscopy (FTIR), Ultraviolet-Visible Spectroscopy (UV-Vis), X-ray diffraction (XRD), and Field Emission Scanning Electron Microscopy (FESEM). Also, the elemental compassion distribution was studied by energy-dispersive X-ray spectroscopy (EDX). In addition, the zeta potential, dynamic light scatter (DLS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) was used to study the stability, thermal properties, and surface area of the SiO₂ NPs. The overall results revealed that the green synthesis of SiO₂ NPs outperforms chemically synthesized SiO₂ NPs. This is expected since the green synthesis method provides higher stability, enhanced thermal properties, and a high surface area through the available phytochemicals in the Rhus coriaria L. extract.