RESUMO
The sustainable synthesis of metal oxide materials provides an ecofriendly and more exciting approach in the domain of a clean environment. Besides, plant extracts to synthesize nanoparticles have been considered one of the more superior ecofriendly methods. This paper describes the biosynthetic preparation route of three different sizes of tetragonal structure SnO2 nanoparticles (SNPs) from the agro-waste cotton boll peel aqueous extract at 200, 500, and 800 °C for 3 h and represents a low-cost and alternative preparation method. The samples were characterized by X-ray diffraction, Fourier transform infrared spectrophotometry, ultraviolet-visible absorption spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and energy-dispersive X-ray spectroscopy. Surface area and porosity size distribution were identified by nitrogen adsorption-desorption isotherms and Brunauer-Emmett-Teller analysis. The photocatalytic properties of the SNP samples were studied against methylene blue (MB) and methyl orange (MO), and the degradation was evaluated with three different size nanomaterials of 3.97, 8.48, and 13.43 nm. Photocatalytic activities were carried out under a multilamp (125 W Hg lamps) photoreactor. The smallest size sample exhibited the highest MB degradation efficiency within 30 min than the most significant size sample, which lasted 80 min. Similarly, in the case of MO, the smallest sample showed a more superior degradation efficiency with a shorter period (40 min) than the large-size samples (100 min). Therefore, our studies suggested that the developed SNP nanomaterials could be potential, promising photocatalysts against the degradation of industrial effluents.
RESUMO
The present report presents a green method for the rapid biogenic synthesis of nanoparticles that offers several advantages over the current chemical and physical procedures. It is easy and fast, eco-friendly, and does not involve any precious elements, hazardous chemicals, or harmful solvents. The synthesized ZnO nanoparticles were characterized using different techniques, such as UV-Visible spectroscopy. The surface plasmon resonance confirmed the formation of ZnO nanoparticles at 344 nm, using UV-Visible spectroscopy. The leaf extract acts as a source of phytochemicals and is primarily used for the reduction and then the formation of stable ZnO nanoparticles by the characteristic functional groups of the extract; the synthesized ZnO nanoparticles were identified using FTIR spectroscopy. The crystalline nature of ZnO-NPs was confirmed via powder X-ray diffraction (XRD). Size and morphology were measured via high resolution transmission electron microscopy (HR-TEM) analysis. The stability of the nanoparticles is established using dynamic light scattering (DLS) and thermogravimetric analysis (TGA). The synthesized ZnO nanoparticles have been found to be a good and efficient catalyst for the synthesis of novel 1,2-dihydro quinazoline derivatives under the green method via a one-pot reaction of 2-amino benzophenone, 1,3-diphenyl-1H-pyrazole carbaldehydes, and ammonium acetate. The synthesized compounds (4a-o) were characterized by the 1H NMR, 13C NMR, and HRMS spectra and were further validated for free-radical scavenging activity. The synthesized ZnO nanoparticles exhibited good antioxidant activity.
