Batch process biosynthesis of silver nanoparticles using Equisetum arvense leaf extract

The plant extract of Equisetum arvense is applied to reduce silver ions to silver nanoparticles (AgNPs) in the batch method. When mixed with silver nitrate (AgNO₃), the extract changed color from yellow to dark brown, and AgNPs were synthesized in 24 h. Plant extracts applied to synthetize metal NPs, provide a simple and eco-friendly approach and the biomolecules are used as reducing and capping agents. The nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy, ultraviolet spectroscopy and X-ray diffraction (XRD) analyses. The dark brown solution showed a surface plasmon resonance of AgNPs around 448 nm. The XRD pattern showed the crystalline nature and high purity of AgNPs. Fourier transform infrared spectroscopy was employed to measure particular functional groups that reduce silver nitrate as AgNPs are formed. TEM revealed that the size of AgNPs was around 18–20 nm. Antibacterial activity assays with Escherichia coli and Staphylococcus aureus demonstrated that AgNPs reduced bacterial growth and produced well-defined inhibition zones.