Figure 5. FT-IR Spectrum of silver nanoparticles.
FTIR analysis was performed to investigate possible organic compounds
involved in the synthesis of nanoparticles. According to Figure 5, after
the reaction with Ag salt, there is some shift in the location and
height of the peaks. This shift is related to the breaking of the bonds
of hydroxyl and carbonyl groups, the release of hydrogen and carbon, and
their role in reducing the charge and regenerating iron ions. The
results of this research showed that the OH and CO groups in the water
extract of the plant are possible compounds for reducing iron salt to
silver nanoparticles. The definitive mechanism of the nanoparticle
formation during green formulation has not yet been determined. Despite
this, some researchers believe that the active surface of terpenoid
molecules causes the regeneration of metal ions and stabilizes the
synthesized nanoparticles [43,44]. Probably, these molecules with or
without other reducing agents (sugars) are effective in this process.
Terpenoids are a large and diverse group of metabolites that are made of
five carbon isoprene structural units and have different types. Since
these substances are the largest group of natural products that exist in
almost all living organisms, it is likely that many plant extracts can
be used in the metal nanoparticle synthesis because of the presence of
terpenoids and reducing sugars in them [45].