Synthesis and Characterization of Nano-Silica from Teff Straw

Efficient utilization of agricultural residue is the need of today's environment. Teff straw is one such agricultural residue which is available in high amount in east African continent particularly Ethiopia. In the present study, combination of heat and acid treatment has been used to extract nano-silica from teff straw. X-ray fluorescence (XRF) analysis showed presence of high amount of silicon dioxide (approximate to 52%) in raw teff straw. Thermal treatment at 600 degrees C for 4 hour increased the SiO2 concentration to approximate to 92% in its ash. Further acid treatment increased the concentration to approximate to 97%. Fourier transform infrared (FTIR) spectroscopy also confirmed increase in SiO2 after thermal and acid treatment. X-ray diffraction (XRD) analysis showed the silica of amorphous nature in teff straw ash before acid treatment (S-BAT) whereas crystallinity increased after acid treatment (S-AAT). Transmission electron microscopy (TEM) showed presence of uniform nano-disks shaped particles of 50 nm average particle size in acid treated teff straw ash. Compared to other agricultural residues high amount of silica availability as raw and its small diameter anatomy structure will make teff straw better source of silica material at lower heat and chemical treatment.