Silver nanoparticle synthesis from Plumbago zeylanica and its dye degradation activity

Silver nanoparticle synthesis using plants has great potential as it is cost-effective, environment-friendly, reproducible and energy saving compared to chemical or physical methods. The present investigation deals with influence of various conditions on silver nanoparticle synthesis from in vitro-grown Plumbago zeylanica. Synthesized nanoparticles were characterized using ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD). UV-Vis spectroscopy confirmed the formation of nanoparticles, FT-IR spectroscopy provided information about functional groups attached to the nanoparticles' surface; XRD analysis illustrated their crystalline structure. The shape (spherical) and size (55 nm) of synthesized nanoparticles was confirmed by using SEM and TEM. The antibacterial activity of silver nanoparticles was evaluated against five bacteria using the disk diffusion method, and a positive result was obtained against four bacteria. The catalytic and photocatalytic degradation efficiency of silver nanoparticles was also evaluated, and it was found that the catalytic efficiency of silver nanoparticles in the case of phenol red, methylene blue and methyl red is higher than in the case of eosin Y, whose photocatalytic degradation showed higher efficiency. This indicates that synthesized silver nanoparticles are capable of degrading organic dyes. This approach can be utilized for degradation of organic dyes at a large scale.