A Comparative Study on Rice Husk, as Agricultural Waste, in the Production of Silica Nanoparticles via Different Methods

Abstract

This study explores the conversion of agricultural waste into valuable industrial precursors, specifically focusing on the production of silica nanoparticles from rice husk (RH) via calcination and sol–gel processes. The synthesized particles underwent detailed analysis to assess their chemical composition, structural features, morphological characteristics, and size distribution. This comparative analysis evaluates the effectiveness of various methods in generating silica from RH and examines the impact of different drying techniques, including freeze-drying and conventional thermal drying, on the properties of the resulting silica nanoparticles. Utilizing a combination of sol–gel and freeze-drying techniques produced spherical nanoparticles with diameters of 10 to 20 nm, characterized by size uniformity, clear contours, and minimal aggregation. X-ray diffraction (XRD) analysis identified the amorphous nature of the silica, as evidenced by diffraction peaks typical of amorphous silica in the RH-derived samples processed via different methods. Significantly, the XRD patterns of the calcination-derived silica showed no foreign peaks, indicating a purer amorphous state. The findings of this study are anticipated to contribute to the development of innovative and efficient silica nanomaterials, fostering the sustainable use of agricultural waste.