Research The Rice Husk Treated By Hydrothermally Treatment

Effective utilization of biomass waste in China which is a large agricultural country is very important, and the output of rice husk as a kind among them is huge. Rice husk treated by hydro thermally treatment can be adjusted to facilitate its surface properties in adsorption, soil modification and so on. The liquid got after hydrothermal can be used for liquid fertilizer. So in the paper rice husk is raw material, which is treated hydrothermally under different condition, to investigate the adsorption characteristics on Cr (VI) and analysis the liquid ingredients got after hydrothermal.Thermal gravimetric analysis and Fourier transform infrared spectroscopy of the rice husk with and without hydrothermal treatment demonstrated some components of rice husk were decomposition after hydrothermal treatment, while producing dehydration condensation product. The effect of different hydrothermal conditions, pH, contact time, initial concentration and temperature on the adsorption capacity were also investigated and several isotherm sorption models and kinetics were used to represent the experimental data. It is showed that the maximum adsorption capacity at pH=1.0 and the rate of adsorption slowly ran up to equilibrium after three hours. The adsorption capacity increased significantly with the increase of temperature and initial concentration. Compared with the raw husk, the product of hydrothermal time 4h, temperature 200℃, the amount of solvent added 40mL remove Cr (VI) best, and at the same condition the amount of removing Cr (VI) using the rice husk with 4 hours treatment is four times that of raw rice husk. The Freundlich adsorption isothermal models and the pseudo-second-order model were fitted well.In order to quest for the possibility about using the liquid products got after hydrothermal as liquid fertilizer, Fourier transform infrared spectroscopy of the liquid products with and without circulating demonstrated the liquid products contained humic substances. At the same time organic content and nitrogen content were respective determined by potassium dichromate and kjedahl determination. It is showed the organic content and nitrogen content in the liquid were both high when circulating the first time during hydrothermal treatment.The results not only to provide a new idea for recycling biomass waste, but also provided a new support in modification of biomass using hydrothermal method.