Low-cost and eco-friendly phyto-synthesis of Silver nanoparticles by using grapes fruit extract and study of antibacterial and catalytic effects

In this research, silver nanoparticles (Ag NPs) were prepared by a low-cost, rapid, simple and ecofriendly approach using Grape fruit extract as a novel natural reducing and stabilizing agent. The product was characterized by UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM). The reaction conditions including time, content of reducing agent and silver nitrate, temperature and pH were investigated. The optimum yield of Ag NPs was obtained when 10 mM of silver nitrate was reacted with 9 mL of Grape fruit extract at pH = 9 and heated it to 55 oC within 25 minutes. The crystalline nature of Ag NPs was confirmed from XRD analysis. SEM and TEM images showed that the obtained Ag NPswere spherical in shape and their sizes were in the range of 25-85 nm.   EDX analysis confirmed presence of the elemental silver. On the basis of FT-IR analysis, it can be stated that the hydroxyl, carbonyl and carboxyl functional groups present in bio-molecules of Grape fruit extract are responsible for the reduction of Ag+ ions and stabilization of the obtained Ag NPs. The biosynthesized Ag NPs showed good antimicrobial activity against Gram-positive (Bacillus cereus, Staphylococcus aureus, Staphylococcus epidermidis) and Gram-negative (Escherichia coli, Klebsiella pneumoniae)bacteria. In addition, the catalytic activity of the Ag NPs wasstudied for the reduction of nitro compounds by using NaBH4.