A new method of comprehensive utilization of rice husk.

Rice husk is an abundant agricultural byproduct. The research on comprehensive utilization of rice husk to prepare xylose, activated carbon and silica was carried out. The hydrolysis conditions of xylan in rice husk to produce xylose were as follows: the concentration of H(2)SO(4) was 3.6% (wt.%), the temperature was 100°C, the ratio of rice husk mass (g) to H(2)SO(4) solution (ml) was 1:5 and the time was 3 h. The hydrolysis degree of xylan reached 95.6%. The resulting residues were used to prepare activated carbons with the BET surface area of 1763 m(2)/g when 50% H(3)PO(4) was impregnated with rice husk with the ratio of 5:1 at 500°C for 0.5 h. The produced carbons had effective adsorption capability to purify the xylose solution. Furthermore, they exhibited good electrochemical performance. After adsorption, activated carbons were calcined to produce silica with the diameter of 30 nm.