Abstract

The use of sorbing additives in removal of U(VI) species from waters by ultrafiltration (UF) has been investigated in long-term studies. Montmorillonite from the Cherkassy field, a natural clay mineral, and Zn–Al–EDTA, a functionalized synthetic layered double hydroxide intercalated with ethylenediaminetetraacetic acid (EDTA), are used as sorbents. The retention coefficient of U(VI) by a UPM-20 membrane in the presence of montmorillonite and Zn–Al–EDTA is 0.88–0.91 and 0.99–0.999, respectively; with no sorbents added, it is lower (0.85–0.89). In the absence of the sorbents, the volume flow rate of uranium-containing waters is at a level of 82–86 dm³/(m² h), whereas, with the sorbents added, this parameter falls (for both sorbents) to 40–50 dm³/(m² h). The contribution of sorbents to the UF filtration of uranium-contaminated waters is identified. Basically, the sorbents act as a dynamic membrane, but their contribution depends mainly on their nature and structure rather than the sorption capacity. The dynamic membrane formed from Zn–Al–EDTA is denser and more robust than the one formed from montmorillonite; therefore, the use of Zn–Al–EDTA in UF purification of uranium-contaminated waters provides considerably better and more stable results. Apart from removing uranium, we investigate the possibility of its concentration. Considerable accumulation of uranium in the relatively small concentrate volume is observed over the entire duration of UF purification process. Thus, the use of sorbing additives considerably improves the indicators of U(VI) removal from water by UF, while enabling us to concentrate U(VI) with the possibility of its further processing.

中文翻译：

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使用蒙脱土和层状双氢氧化物Zn-Al-EDTA形成的动态膜，通过超滤去除水中的U（VI）

摘要

在长期研究中，已经研究了使用吸附添加剂通过超滤（UF）去除水中的U（VI）物质的方法。来自Cherkassy油田的蒙脱石（一种天然粘土矿物）和Zn-Al-EDTA（一种嵌入乙二胺四乙酸（EDTA）的功能化合成层状双氢氧化物）用作吸附剂。在蒙脱石和Zn-Al-EDTA存在下，UPM-20膜对U（VI）的保留系数分别为0.88-0.91和0.99-0.999。在不添加吸附剂的情况下，该值较低（0.85-0.89）。在没有吸附剂的情况下，含铀水的体积流量为82–86 dm ³ /（m ² h），而添加吸附剂时，该参数（对于两种吸附剂）均降至40 –50 dm ³ /（米²H）。确定了吸附剂对铀污染水超滤的贡献。吸附剂基本上起动态膜的作用，但其贡献主要取决于其性质和结构，而不是吸附能力。与由蒙脱石形成的动态膜相比，由Zn-Al-EDTA形成的动态膜更致密，更坚固。因此，在铀污染水的超滤提纯中使用Zn-Al-EDTA可提供更好，更稳定的结果。除了去除铀，我们还研究了其浓缩的可能性。在超滤纯化过程的整个过程中，观察到铀在相对较小的精矿体积中大量积累。因此，使用吸附添加剂可显着改善UF从水中去除U（VI）的指标，