Abstract Recently, clays have been investigated for the long-term storage of spent nuclear fuel and nanominerals have been developed for the separation of radionuclides from subsurface water, but the detailed structure relating to pillaring of the sorbent is not always easily assessable by X-ray diffraction, for example, where the shift of the basal spacing to a higher value is not distinct. The purpose of this study was to gain an insight into the correlation between nanoscale structure and macroscopic sorption performance. The time dependence of 239‑plutonium sorption to Laponite, (Ce Al)-Laponite, and (Ce Al)-bentonite was studied. (Ce Al)-Laponite was characterized by TEM, XPS, XRD, N2 adsorption/desorption isotherms, and small-angle neutron scattering. Analysis of neutron scattering from dry powder and powder dispersed in water showed that (Ce Al)-Laponite has an open pore-fractal structure described by a fractal dimension Dp = 2.5, and a radius of gyration Rg = 6.5 nm. In a slightly alkaline pH condition, the strength of the sorption (Kd) of 239Pu by the different sorbents, from most to least, was (Ce Al)-bentonite (104) > (Ce Al)-Laponite (~104) > Laponite (103) > bentonite (103). The time it took for Pu sorption to reach equilibrium for (Ce Al)-Laponite was almost two times faster than that observed for the starting clays and the (Ce Al)-bentonite (8 days). A pseudo-second order rate expression was applied to the time-course data to describe the kinetic behavior. The enhanced rate of sorption was attributed to the connected pore system present in (Ce Al)-Laponite.

中文翻译：

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分形状 (Ce Al)-氧化物锂皂石簇中的孔结构和钚保留

摘要 最近，粘土已被研究用于长期储存乏核燃料，纳米矿物已被开发用于从地下水中分离放射性核素，但与吸附剂柱状结构相关的详细结构并不总是很容易通过 X 射线评估。例如，衍射，其中基底间距向更高值的偏移并不明显。本研究的目的是深入了解纳米级结构与宏观吸附性能之间的相关性。研究了 239 钚吸附到合成锂皂石、(Ce Al)-合成锂皂石和 (Ce Al)-膨润土的时间依赖性。(Ce Al)-Laponite 通过 TEM、XPS、XRD、N2 吸附/解吸等温线和小角度中子散射表征。对干粉和分散在水中的粉末的中子散射分析表明，(Ce Al)-Laponite 具有开放的孔隙分形结构，其分形维数 Dp = 2.5，回转半径 Rg = 6.5 nm。在弱碱性 pH 条件下，不同吸附剂对 239Pu 的吸附强度（Kd）从大到小依次为（Ce Al）-膨润土（104）>（Ce Al）-Laponite（~104）> Laponite (103) > 膨润土 (103)。(Ce Al)-锂皂石的Pu 吸附达到平衡所花费的时间几乎是起始粘土和(Ce Al)-膨润土所观察到的时间的两倍（8 天）。将伪二级速率表达式应用于时程数据以描述动力学行为。吸附速率的提高归因于 (Ce Al)-Laponite 中存在的连通孔系统。