Lignocellulose aerogel and amorphous silica nanoparticles from rice husks

Rice Husks (RHs) are one of the most abundant sources of biomass in the world due to rice consumption. Lignocellulose and silica are two of the main components of RHs, which allow RHs to be applied in different areas. Lignocellulose can be partially dissolved in 1-butyl-3-methylimidazolium chloride (BMIMCl), which is a simple way of competing with the traditional extraction methods that suffer from high chemical consumption. A lignocellulose freeze gel is obtained via a cyclic liquid nitrogen freeze-thaw (NFT) process. Multi-functional self-assembled lignocellulose aerogel is obtained after CO2 supercritical drying. Based on the aerogel’s special properties, two routes are developed for practical applications. On one hand, the aerogel is coated to exhibit a superhydrophobic property that can be applied as an absorbent for oil spills. On the other hand, a carbon aerogel is synthesized via a pyrolysis process, resulting in a porous amorphous carbon. The residue after partially dissolving lignocellulose in BMIMCl is further calcined to obtain amorphous silica nanoparticles, achieving a comprehensive application of RHs.