Beyond waste: waste rice husk to value-added products using sonic waves and chemical treatment and principal component analysis of extraction

This study mainly focussed on the chemical pre-treatment of waste rice husk using sodium hydroxide followed by sonication to extract cellulose, hemicellulose, and lignin. This paper also reported the production of bioethanol using Aspergillus sp. and Saccharomyces sp. The highest amount of ethanol production was observed from 4% NaOH pre-treated sonicated rice husk, that is, 30.40 mg/g. This study also estimated the xylan content in the hydrolysate after lignin extraction. The highest amount of xylan was estimated in 2% NaOH pre-treated non-sonicated hydrolysate, that is, 8.24%. Furfural was also produced from extracted cellulose and extraction of furfural was 15%, produced from 2% NaOH pre-treated non-sonicated rice husk. This paper also focused on the optimization and yield of the process to extract different value-added products utilizing rice husk as a raw material. By extracting various products in different steps of the process, this study deals with the zero-waste idea by minimizing the waste materials and contributing toward the generation of clean energy.