A Statistical Approach for Biogenic Synthesis of Nano-Silica from Different Agro-Wastes

Abstract

Biogenic silica is an excellent alternative to synthetic silica because of its capricious configuration, density, composition, less toxicity, environmentally friendly synthesis and cost-effective preparations. Among the available agricultural bioresources, we have chosen groundnut shell, banana peel, coconut husk, orange peel and walnut shell as an economical and non-metallic bio-precursor for biogenic nano-silica synthesis. Here we stake out the extraction of nanostructured silica from readily available agricultural waste sources like groundnut shell, banana peel, coconut husk, orange peel and walnut shell using an alkali leaching extraction method. Entomotoxic activity of these silica nanostructures was investigated against Sitophilus oryzae mostly present in the stored rice and other grains. The SEM and TEM images showed that the extracted biogenic nano-silica results in an assortment of agglomerated nano-sized particles. The nature of the chemical bonding of extracted powder were characterized using X-ray powder diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) results authenticate that the extracted amorphous silica from transforms. The morphology and elemental composition of the extracted silica powder were studied by scanning electron microscopy (SEM) Transmission Electron Microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDAX), respectively. Optimization of biogenic nano-silica synthesis using response surface methodology was used to study the effect of overall input variables and to obtain maximum production.