Yield and properties of nanobiosilica extracted from rice husk using technical grade chemicals: effect of extraction temperatures and times

Abstract

Silica particles contained in rice husk (RH) are valuable materials with various industrial applications. However, simple and feasible techniques for large-scale production of silica nanoparticles from RH (nanobiosilica) remain challenging. This study was aimed to investigate the influence of extraction temperatures and times on the yield and characteristics of nanobiosilica extracted from rice husk ash (RHA) using technical grade chemicals. The nanobiosilica was extracted from RHA using a simple sol-gel technique at three temperatures (25, 50, and 70 ˚C) for three extraction times (1, 2, and 3 h). The results showed that the extraction yield of nanobiosilica was significantly influenced by the extraction temperatures and times. The highest extraction yield (67.2%) was obtained at a temperature of 70 ˚C for 3 h. The use of technical grade chemicals affected the quality of nanobiosilica produced. The concentration of SiO2 in nanobiosilica from the best treatment was 86.21%. The presence of asymmetric Si-O-Si functional group was observed at 1101.68 cm−1 wavelength. The nanobiosilica produced had particle sizes of 25.1-40.6 nm, bulk density of 0.67-0.81 g/mL, and averaged crystallinity degree of 58.50%. The best extraction technique developed may be used for large-production of nanobiosilica from RHA, depending on technical specifications required for further applications.