A study on the consecutive preparation of d-xylose and pure superfine silica from rice husk
2010
Zhang, Hongxi | Zhao, Xu | Ding, Xuefeng | Lei, Hong | Chen, Xue | An, Dongmin | Li, Yunling | Wang, Zichen
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 H₂SO₄ is 4% (wt.%), the temperature is 130°C, the ratio of rice husk mass (g) to H₂SO₄ solution volume (ml) is 1:4 and the time is 2h. 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 H₂SO₄. Residuals from H₂SO₄ pre-treatment are incinerated under 750°C in stationary air for 15min. 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 30-200nm and specific surface 287.86m²/g.
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