Adsorptive Property of Rice Husk for Uranium

The adsorption experiments were researched by using the rice husk powder as the adsorbent to remove the U(Ⅵ) from aqueous solution.The affecting factors on the U(Ⅵ) removal rate such as rice husk particle size,pH,initial concentration,adsorption time,temperature and dosage of adsorbent were evaluated,kinetics and adsorption isotherm law were analyzed,and mechanisms for U(Ⅵ) removal were discussed by SEM,FT-IR and energy spectrum analysis.The results show that U(Ⅵ) removal rate increases with the decrease of the size of adsorbent,and with the increase of adsorbent dosage and temperature.The process of adsorption can be described by an equation of pseudo 2nd-order mode,and the relation coefficient is 1.The process of adsorption also fits to Freundlich isotherm(R2=0.995 4).The adsorption of uranium on rice husk changes the surface form of rice husk.Hydroxyl,carboxylic,P—O and Si—O are the main functional groups in the reaction with U(Ⅵ).The adsorption mechanism is mixture adsorption,including the physical and chemical adsorption.