Adsorptive Characteristic of U(Ⅵ) by Modified Rice Stem

Static adsorption experiments were carried out to study the influence of the modifying agents, the amount of rice stem as the adsorbent, pH, temperature, etc. on the adsorption of U(Ⅵ). The sorption isotherm equations and the kinetic models were used to fit the experimental data. The results show that the rice stem can be modified effectively by 0.5 mol/L NaOH, and that at the optimum adsorption conditions, i.e. pH=4.0, 180 min of the adsorption time, 5.8 g/L of the amount of adsorbent, the good adsorption behavior is very good with the removal at room temperature. With increases of the initial concentration of U(Ⅵ), the removal rate of U(Ⅵ) is decreased. Under the best experimental conditions, the removal rate of U(Ⅵ) reaches 99.72%. The removal process of U(Ⅵ) by using modified rice stem fits to Langmuir isotherm equation and the correlation coefficients r² is up to 0.9899. The process of adsorption can be well described by pseudo second order model with the relation coefficient to 0.9992.