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In this investigation we report the synthesis of nano silica (NS) nanoparticles from barley grass waste-an environmental burden-using varying temperatures during preparation. The temperatures used during the investigation were 400, 500, 600, and 700ºC, and we studied its effects on the mechanical properties of the NS nanoparticles for use in environmentally friendly applications. Furthermore, the NS nanoparticles resulting from high temperature synthesis were characterized using various characterization methodologies such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, Brunauer-Emmett-Teller (BET), Fourier transform infrared (FTIR) and X-ray fluorescence (XRF) spectrometry analysis. The result of the various characterizations revealed the presence of elemental Si, C, and O in the synthesized nanoparticles. Using XRF, we observed that higher amounts of SiO 2 particles from NS were obtained at 600ºC and 700ºC, also resulting in higher strength in the mechanical properties. Furthermore, using the Brunauer-Emmett-Teller (BET) methodology, we were able to measure the surface area corresponding to 150 m 2 /g. Additional methodologies were used, such as differential scanning calorimetric (DSC), thermo gravimetric analysis (TGA), SEM, and tensile analysis. The results of this study showed improved and stable mechanical properties with the increase in temperature during synthesis.

Water contamination by petroleum and its byproducts presents a major challenge worldwide. It is critical that sustainable treatment methods be employed for the removal of such contaminants from polluted water. For this investigation, magnetic nano silica (M-NS) was synthesized using agricultural waste from barley husk using a two-step process that is environmentally friendly and uses green chemistry synthesis. The barley husk waste was used as a precursor for the synthesis of nano-silica following a low energy and sustainable method of acid reflux and heat treatment. Nano-silica was then used for the synthesis of M-NS, with the addition of a magnetic solution of Fe3O4 nanoparticles. The magnetic nano-silica particles were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Zeta potential analysis (ZETA) and X-Ray Diffraction (XRD). Magnetic nano-silica particles were observed to have an average diameter of 162 nm and appeared to be hydrophobic, with a large surface area of ~120 m2/gm. Due to these characteristics, magnetic nano-silica was used as an adsorbent for the removal of petrol contaminants from water. The experimental procedure showed that only 0.6 gm. of M-NS was used on 40 mg/L concentration of petroleum and the experiments recorded a high uptake efficiency of 85%. The sorption was shown to be an effective process since a high amount of petroleum was removed. The study further demonstrates that as the amount of sorbent is increased, the sorption capacity also increases until an equilibrium is reached. The results of this study establish that synthesis of M-NS, using environmentally sustainable processes, has the required characteristics to serve as sorbent for petroleum and its byproducts from contaminated water, thus enhancing environmental sustainability.

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