Kim June-Hyun, Kim Sung-Man, Yoon In-Ho, Kim Ilgook
Decommissioning Technology Research Division, Korea Atomic Energy Research Institute 111, Daedeok-daero 989 Beon-gil, Yuseong-gu Daejeon 305-353 Republic of Korea
School of Architectural, Civil, Environmental, and Energy Engineering, KyungPook National University 80 Daehak-ro, Sangyeok-dong, Buk-gu Daegu Republic of Korea.
RSC Adv. 2020 Jun 8;10(37):21822-21829. doi: 10.1039/d0ra03426f.
The separation of Cs-enriched fine particles is a highly effective way to reduce the volume and radioactivity of contaminated soil. This work demonstrated the application of polyethylenimine (PEI)-coated FeO nanocomposites and a mesh filter for the selective separation of clay particles from Cs-contaminated soil. The PEI coating on the FeO nanoparticles enhanced the binding force between the magnetic nanoparticles and clay minerals electrostatic attraction; thus, approximately 100% of the clay particles were magnetically separated from solution by FeO-PEI nanocomposites at a low dose (0.04 g-nanocomposite per g-clay). In separation experiments with soil mixtures, clay- and silt-sized fine particles that had been magnetized by FeO-PEI nanocomposites were selectively separated, and the separation efficiency improved when a mesh filter was added to exclude physically large particles. The combination of magnetic and sieving separation thoroughly separated fine particles from soil by reducing the volume of the magnetic fraction. We also evaluated the magnetic-sieving separation method for the selective removal of clay particles from Cs-contaminated soil. The decrease in radioactivity in the treated nonmagnetic fraction, which accounted for 87.5% of the total soil, corresponded to a high decontamination efficiency of approximately 90%. The developed separation technology offers great potential for the efficient remediation of radioactive soil.
富集铯的细颗粒分离是减少污染土壤体积和放射性的一种高效方法。这项工作展示了聚乙烯亚胺（PEI）包覆的FeO纳米复合材料和筛网过滤器在从铯污染土壤中选择性分离粘土颗粒方面的应用。FeO纳米颗粒上的PEI涂层增强了磁性纳米颗粒与粘土矿物之间的结合力——静电吸引力；因此，在低剂量（每克粘土0.04克纳米复合材料）下，FeO-PEI纳米复合材料能从溶液中磁分离出约100%的粘土颗粒。在土壤混合物的分离实验中，被FeO-PEI纳米复合材料磁化的粘土和粉砂大小的细颗粒被选择性分离，并且当添加筛网过滤器以排除物理尺寸较大的颗粒时，分离效率提高。磁分离和筛分分离相结合，通过减少磁性部分的体积，将细颗粒与土壤彻底分离。我们还评估了磁筛分分离方法从铯污染土壤中选择性去除粘土颗粒的效果。处理后的非磁性部分占土壤总量的87.5%，其放射性的降低对应着约90%的高去污效率。所开发的分离技术为放射性土壤的高效修复提供了巨大潜力。
