膨润土对U(Ⅵ)的吸附机理研究

Taking Gaomiaozi bentonite as the research object, through static adsorption experiments, the adsorption characteristics of Gaomiaozi bentonite for U(Ⅵ) were investigated, and the effects of factors such as contact time, solid-liquid ratio, initial concentration of uranium, pH, ion type and ion concentration on the adsorption characteristics of U(Ⅵ) were studied, and the adsorption kinetic and thermodynamic processes of bentonite for U(Ⅵ) were discussed. The results show that: the adsorption process reaches a dynamic equilibrium after 24 h; the optimal adsorption solid-liquid ratio is 1:300; the optimal initial adsorption concentration is 40 mg·L~(-1); when the pH is 5, the adsorption effect of bentonite on U(Ⅵ) is the best, and being too acidic or too alkaline will affect the adsorption of U(Ⅵ) by bentonite; Ca~(2+) and CO_3~(2-) in the solution significantly reduce the adsorption effect of bentonite on U(Ⅵ), and the degree of influence increases with the increase of ion concentration; the Freundlich isothermal adsorption model and the pseudo-second-order kinetic model have a good fitting effect on the adsorption process, mainly manifested as multi-layer adsorption.

以高庙子膨润土为研究对象,通过静态吸附实验,考查了高庙子膨润土对U(Ⅵ)的吸附特征,研究了接触时间、固液比、铀的初始浓度、pH、离子类型和离子浓度等因素对U(Ⅵ)吸附特征的影响,并讨论了膨润土对 U(Ⅵ)的吸附动力学和热力学过程。结果表明:吸附过程在24 h后达到动态平衡;最佳吸附固液比为1:300;最佳吸附初始浓度为40 mg·L~(-1);在pH为5时,膨润土对U(Ⅵ)的吸附效果最好,过酸或过碱都会影响膨润土对 U(Ⅵ)的吸附;溶液中Ca~(2+)、CO_3~(2-)显著降低了膨润土对U(Ⅵ)的吸附效果,影响程度随着离子浓度的增加而增大;Freundlich等温吸附模型和准二级动力学模型对吸附过程的拟合效果较好,主要表现为多层吸附。