Synthesis and characterization of silver nanoparticles using reducing agents of bitter leaf (Vernonia amygdalina) extract and tri-sodium citrate

Abstract

The aim of this work was to synthesize silver nanoparticles (AgNPs) using trisodium citrate and extract obtained from Vernonia amygdalina plant leaves as a chemical and biological reducing agent, respectively, and to investigate the impact of different experimental conditions on the stability and particle size of the acquired nanoparticles. Particle size analyzers, UV–Vis​ spectrophotometry, Fourier-transform infrared spectroscopy (FTIR) analysis and X-ray diffraction (XRD) were used to characterize the synthesized AgNPs. During the reduction reaction, a notable change in the color of the colloidal solution from colorless to gray indicated that the Ag+ ion was reduced to Ag0. The maximum absorption in the UV–Vis spectra for the acquired AgNPs in aqueous solution had wavelengths of 452 and 437 nm, respectively, for the biological and chemical methods. The average particle sizes of the prepared AgNPs using the green and chemical reducing agents were found to be 63.08 and 38.47 nm, respectively. FTIR characterization on dry powders of the AgNP samples showed different features for the functional groups and phytochemicals. The XRD patterns have confirmed that the powder particles of the AgNPs are crystalline in nature, with the face centered cubic phase (FCC). It was found that the AgNPs that were prepared by the green method had more stability than those prepared by the chemical method. The green method is simple, affordable, eco-friendly and green compared to the chemical method.