The extraction of lignocelluloses and silica from rice husk using a single biorefinery process and their characteristics

While the efficient usage of biomass waste can significantly help in addressing environmental issues, there are only a few reports that discuss about processing such waste effectively at a low-cost. Such challenge arises from the strong association between the components biomass. In this study, an abundant agricultural byproduct, rice husk (RH), was used as the starting resource. A simple biorefining process of alkaline peroxide treatment followed by acid precipitation and ethanol extraction was performed on RH to obtain cellulose, hemicellulose, lignin, and silica. The chemical structures, morphologies, and physic-chemical properties of the separated components were identified through a wide range of characterization approaches. The final products obtained from of this process were (i) bundles of fiber-like cellulose with a fiber width of 6 µm and (ii) small particles of hemicellulose and lignin with non-uniform shapes. The lignocelluloses products had over 90 wt% carbon with 52.28% crystalline ratio. Meanwhile, the other products comprising hemicelluloses, lignin, and silica were amorphous. The outcome of this study contributes to expanding and developing the simple and efficient conversion process of biomass waste into sustainable value-added materials. It is crucial to reduce the environmental impact by using renewable materials as the new building block resources for synthetic chemicals.