Production of Biogenic Silica Nanoparticles by Green Chemistry Approach and Assessment of their Physicochemical Properties and Effects on the Germination of Sorghum bicolor

The synthesis of phyto-extract-assisted nanomaterials is very popularity as the process is simple and inexpensive. Euphorbia thymifolia L. belongs to family Euphorbiaceae and it is well-known herb species. The aim of the present research is a green synthesis of silica nanomaterials using the aqueous extract of E. thymifolia. The synthesized silica nanoparticles were characterized by Ultraviolet-visible (UV-Vis) spectrophotometer, Fourier Transform Infrared Spectroscopy (FTIR), X-Ray diffraction analysis (XRD), Scanning Electron Microscope (SEM) with Energy Dispersive X-ray Analysis (EDAX), Dynamic Light Scattering (DLS) and Thermogravimetric analysis (TGA). These results confirmed the successful formation of nanoparticles, which are spherical and amorphous in nature. EDAX analysis determined the purity of the silica nanoparticles, which are composed of Si and O elements with no other impurities. XRD spectroscopy illustrates that characteristic diffraction peaks for silica nanoparticles were observed at 2 theta range 20 degrees corresponding to 101 planes. The average size of synthesized silica nanoparticles is 17 nm. The surface charge and stability of silica nanomaterials were analysed using dynamic light scattering (DLS), which revealed that the synthesized nanomaterials have a negative charge (-2.00 mV). The results obtained from this investigation confirm that the aqueous extract of E. thymifolia can play a vital role in the capping and stabilization of Tetra Ethyl Ortho Silicate to silica nanoparticles. In addition, the effect of bio-synthesized silica nanoparticles on the germination of Sorghum bicolor was determined, and it was concluded that silica nanoparticles improved the percentage of seed germination and that it would be useful for agricultural application.