改性稻秆吸附U(Ⅵ)的特性研究

Adsorptive Characteristic of U(Ⅵ)by Modified Rice Stem

通过静态吸附实验,以稻秆为吸附剂、含U（Ⅵ）溶液为吸附质,研究了吸附剂改性方法、吸附剂用量、溶液pH值、吸附温度等因素对稻秆吸附U（Ⅵ）效果的影响,探讨了改性稻秆吸附U（Ⅵ）的热力学、动力学性质。实验结果表明,用0.5mol/L NaOH能够对稻秆进行有效改性,在吸附pH=4.0、吸附时间为180min、改性稻秆投加量为5-8g/L、室温条件下,改性稻秆吸附U（Ⅵ）可达到较好吸附效果,U（Ⅵ）去除率达到99.72%;但随着铀初始质量浓度的增加,U（Ⅵ）去除率降低。改性稻秆吸附U（Ⅵ）的热力学过程遵循Langmuir等温吸附方程,相关系数r^2=0.989 9;改性稻秆吸附U（Ⅵ）的动力学过程符合准二级动力学方程,相关系数r^2达到0.999 2。

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 r^2 is up to 0. 989 9. The process of adsorption can be well described by pseudo-second-order model with the relation coefficient to 0. 999 2.