In this paper, the green synthesis of silver nanoparticles (AgNPs) using
Psidium guajava leaf extract at room temperature. The prepared silver
nanoparticles were characterized using UV-Vsible Spectroscopy, Transmission
Electron Microscopy (TEM), X-ray diffraction (XRD), Fourier transform
infrared (FTIR) and Thermal gravimetric analysis (TGA). The effects of extract
concentration, extract pH and contact time on the size and shape of silver
nanoparticles are studied. The data revealed that the rate of formation of
nanosilver increased significantly in the basic medium and with increasing
temperature. TEM studies showed that the particles to be of various shapes and
sizes. X-ray diffraction (XRD) study confirmed crystalline nature of the
synthesized nanoparticles. FTIR measurement showed that the silver
nanoparticles having a coating of the extract compounds indicating a possible
role of groups of phenolic compounds that act as a capping and stabilizing
agents for the formed silver nanoparticles. Thermo gravimetric analysis (TGA)
was carried out to determine the amount of capping phytochemicals on the silver
nanoparticles. Supposed mechanism for the formation of silver nanoparticles is
discussed.
Keywords: Green synthesis, Psidium guajava, leaf extract, Ag NPs.