Silica removal by alkaline hydrogen peroxide treatment to enhance the conversion of rice straw to sugars

Abstract

The massive production of rice straw could eventually lead to uncontrolled air pollution due to open burning activity. In this study, the rice straw was treated with alkaline hydrogen peroxide (AHP) to remove silica as well as to maximize the hydrolysis of the treated rice straw. Thus the study aimed to determine the effects of reaction parameters (i.e. AHP concentrations, particle sizes of rice straw, and temperature) towards the pretreatment with AHP in a batch system. From the characterization analysis, the rice straw sample contained high amount of silica (20%) and lignin (20%). From the study, >83.8% silica removal, 80% of delignification, and 7.88% of reduced sugar were achieved at optimum conditions of 60 °C with 10% AHP solution for sample with <0.5 mm particle size. From this study, the increase in AHP concentrations and temperature resulted in higher removal of silica and higher hydrolyzed sugar produced. Particle size did not caused significant effect towards the silica removal but contributed significantly towards the sugar production. Hence, it can be concluded that this study has depicted that the selected processes for silica removal from rice straw are indeed suitable to increase sugar production from biomass.