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 H2SO4 was 3.6% (wt.%), the temperature was 100°C, the ratio of rice husk mass (g) to H2SO4 solution (ml) was 1:5 and the time was 3h. The hydrolysis degree of xylan reached 95.6%. The resulting residues were used to prepare activated carbons with the BET surface area of 1763m2/g when 50% H3PO4 was impregnated with rice husk with the ratio of 5:1 at 500°C for 0.5h. 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 30nm.