3 research outputs found
Influence of Different Plants Extracts on Silver Nanopar ticles Green Synthesis
Three plants extracts were used for biosynthesis of Ag nanoparticles (AgNPs). AgNPs nucleation process requires effective reduction agents which secure Ag+ to Ag0 reduction and also stabilizing/capping agents. The UV-vis and TEM observation revealed
that the best results were obtained by R. officinalis leaf extract. The strong SPR band peak appeared at the wavelength 418 nm.
Synthetized AgNPs were globular, fine (~20 nm), uniform and stabile throughout the experiment. A rapid rate of AgNPs synthesis
was also significant and economically advantageous factor. Fine (10-20 nm) and globular nanoparticles were synthetized also by U.
dioica leaf extract, but the stability of nanoparticles was not permanent. Despite V. vitis-idaea fruit extract contains a lot of reducing
agents, UV-vis did not confirm the presence of AgNPs in solution. Synthetized Ag particles were very unstable, Ag particles
agglomerated very fast and clearly indicated sediment was formed
Characteristics of Silver Nanoparticles in Different pH Values
Stability of silver nanoparticles strongly influences the potential of their application. The literature shows wide possibilities
of nanoparticles preparation, which has significantly impact on their properties. Therefore, the improvement of AgNPs preparation
plays a key role in the case of their practical use. The pH values of the environment are one of the important factors, which
directly influences stability of AgNPs. We present a comparing study of the silver nanoparticles prepared by „bottom-up“ methods
over by chemical synthesis and biosynthesis using AgNO3 (0.29 mM) solution. For the biosynthesis of the silver nanoparticles,
the green freshwater algae Parachlorella kessleri and Citrus limon extracts were used as reducing and stabilizing agents. Chemically
synthesized AgNPs were performed using sodium citrate (0.5%) as a capping agent and 0.01% gelatine as a reducing agent.
The formation and long term stability of those silver nanoparticles synthesized either biologically and chemically were clearly
observed by solution colour changes and confirmed by UV-vis spectroscopy. The pH values of formed nanoparticle solutions were
3 and 5.8 for biosynthesized AgNPs using extract of Citrus limon and Parachlorella kessleri, respectively and 7.2 for chemically
prepared AgNPs solution using citrate. The SEM as a surface imaging method was used for the characterization of nanoparticle
shapes, size distribution and also for resolving different particle sizes. These micrographs confirmed the presence of dispersed and
aggregated AgNPs with various shapes and sizes