SRI Center for Physical Sciences and Technology, Radiochemistry Laboratory, Savanorių ave 231, Vilnius, LT-02300, Lithuania.
J Environ Radioact. 2012 Jun;108:41-9. doi: 10.1016/j.jenvrad.2011.07.012. Epub 2011 Sep 21.
Kinetics of Pu(IV) and Am(III) sorption from natural groundwater to three types of clays were studied at trace concentrations of the elements. Higher K(d) values were determined for sorption of Pu than of Am, and no clear dependence of the K(d) values and the kinetic coefficients on the composition of the clays can be deduced. Kinetic data evaluated by models for six different control processes indicated a sorption mechanism controlled by Pu or Am diffusion in the inert layer on the surface of the clays. Apart from the kinetics of the elements sorption, time-dependent changes in their bonding nature were also studied using a sequential extraction. It was found that Pu(IV) was predominantly associated with amorphous and crystalline Fe oxides as well as natural organic matter sites on the clays, whereas in the case of Am(III) the exchangeable and carbonate sites played the principal role.
研究了痕量条件下三种类型粘土对 Pu(IV)和 Am(III)的吸附动力学。Pu 的吸附 K(d) 值高于 Am 的吸附 K(d) 值，且不能从粘土的组成来推断 K(d) 值和动力学系数的明显依赖性。通过六种不同控制过程模型评估的动力学数据表明，吸附机制受 Pu 或 Am 在粘土表面惰性层中的扩散控制。除了元素吸附的动力学外，还使用顺序提取研究了它们键合性质随时间的变化。结果发现，Pu(IV)主要与粘土上的无定形和结晶 Fe 氧化物以及天然有机质位点结合，而对于 Am(III)，可交换和碳酸盐位点起主要作用。
