Integrated bio-refinery process for mass production of silica, lignin, and nanocellulose from rice straw biomass

Abstract

ABSTRACT An efficient integrated bio-refinery process was established for mass production of silica, lignin, and nanocellulose from rice straw lignocellulose. A three-step process was used for achievement of three value-added products as: silica, lignin, and nanocellulose. At the first step of process, sodium hydroxide of 18% dosage was used as pulping agent to dissolve lignin, silica and other substances in rice straw to obtain cellulose pulp and black liquor. At the second step, silica powder and lignin are recovered by precipitation with sulfuric acid at suitable pH. Third step of process is nanocellulose fabrication from bleached cellulose pulp using a mixture of H2SO4 and H2O2. The suitable technical parameter for silica, lignin, and nanocellulose fabrication was established. At suitable condition, the silica, lignin, and nanocellulose yields were about 9.5%, 12.4%, and 28.7%, respectively, compared to the starting material in experimental scale. Moreover, this bio-refinery process was scaled-up for mass production of three products with relative high yields. The as-obtained products were characterized by SEM, IR, and XRD for determine the structure and morphology.