A study on the consecutive preparation of d-xylose and pure superfine silica from rice husk

• Published in: Bioresource technology 2010-02, Vol.101 (4), p.1263-1267
• Main Authors: Zhang, Hongxi, Zhao, Xu, Ding, Xuefeng, Lei, Hong, Chen, Xue, An, Dongmin, Li, Yunling, Wang, Zichen
• Format: Article
• Language: English
• Subjects: acid hydrolysis; Adsorption; Biological and medical sciences; Consecutive preparation; d-Xylose; Food industries; Fundamental and applied biological sciences. Psychology; hydrolysates; Hydrolysis; Metals - chemistry; Oryza - chemistry; Oryza sativa; Oxides - chemistry; Porosity; Powders; raw materials; rice hulls; Rice husk; silica; Silicon Dioxide - chemical synthesis; sulfuric acid; Sulfuric Acids - chemistry; Superfine silica; Temperature; Time Factors; Use and upgrading of agricultural and food by-products. Biotechnology; xylan; xylose; Xylose - chemical synthesis
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2009.09.045

Rice husk is an abundant agricultural byproduct. In the present paper, research on consecutive preparation of d-xylose and superfine silica from rice husk is carried out. The optimum hydrolysis conditions of xylan in rice husk to d-xylose are as follows: the concentration of H 2SO 4 is 4% (wt.%), the temperature is 130 °C, the ratio of rice husk mass (g) to H 2SO 4 solution volume (ml) is 1:4 and the time is 2 h. The hydrolysis degree of xylan reaches 96.22% (wt.%). High purity (98.5%, wt.%) d-xylose is obtained from acid hydrolysis solution with the purification yield of 71.63% (wt.%). At the same time, the metal oxides in rice husk are efficiently dissolved by H 2SO 4. Residuals from H 2SO 4 pre-treatment are incinerated under 750 °C in stationary air for 15 min. Silica is obtained with the purity of 99.87% (wt.%). The superfine silica powder is obtained after ground and ultrasonic dispersion, with the diameter of 30–200 nm and specific surface 287.86 m 2/g.