Obtención y Caracterización de Nanopartículas de Sílice (SiO₂) a Partir de Biochar de Cáscara de Arroz: Una Estrategia de Valorización de Residuo Agroindustrial

Abstract

This study focuses on the valorization of residual rice husk, emphasizing the obtaining of high-value added silica (SiO₂) nanoparticles. The raw material, previously purified with 0.1 N HCl, was subjected to pyrolysis at 400 °C in a fixed-bed reactor, yielding a high biochar production (55.0wt%). The biochar was converted into silica through a controlled thermal treatment up to 600 °C, followed by an acid-washing purification. Characterization of the final product revealed a highly texturized and porous nanostructure, composed of aggregates of primary particles ranging from ∼5 to 25 nm (TEM). Elemental analysis (EDS) confirmed that the final matrix is mainly siliceous (O: 47.8 wt%; Si: 40.6 wt%), demonstrating that the sequence of pyrolysis and post-treatment is an effective strategy for obtaining nanostructured silica from agro-industrial waste.