Synthesis and characterization of biosilica gel produced from teff (Eragrostis tef) straw using the sol-gel technique

Abstract

In this work, biosilica gel was synthesized using the sol-gel method from teff straw. Silica gel was synthesized from teff straw ash prepared at calcination temperatures of 500 to 900 °C using a 2.5 N NaOH solution. The silica gel yield increases with calcination temperature from 500 to 800 °C and decreases at 900 °C. The maximum yield (94.2 %) was attained at 800 °C. Further, the physiochemical and morphological characteristics of silica gel were characterized using FTIR, XRD, SEM, EDX, and BET. The silica gel functional group-specific characteristic peaks were only seen in FT-IR spectra, and amorphous silica gel was confirmed by XRD. By using SEM, the surface structure was identified. The performance of silica gel with a purity of 99.39 % and the highest surface area of 807.163 m2/g, a pore volume of 0.34 cm3/g, and a pore diameter of 1.70 nm was observed at 700 °C.