Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev , Midreshet Ben Gurion, 08990 Israel.
Nuclear Research Center of the Negev , P.O. Box 9100, Beer Sheva 84190, Israel.
Environ Sci Technol. 2015 Nov 17;49(22):13275-82. doi: 10.1021/acs.est.5b03383. Epub 2015 Oct 27.
Migration of colloids may facilitate the transport of radionuclides leaked from near surface waste sites and geological repositories. Intrinsic colloids are favorably formed by precipitation with carbonates in bicarbonate-rich environments, and their migration may be enhanced through fractured bedrock. The mobility of Ce(III) as an intrinsic colloid was studied in an artificial rainwater solution through a natural discrete chalk fracture. The results indicate that at variable injection concentrations (between 1 and 30 mg/L), nearly all of the recovered Ce takes the form of an intrinsic colloid of >0.45 μm diameter, including in those experiments in which the inlet solution was first filtered via 0.45 μm. In all experiments, these intrinsic colloids reached their maximum relative concentrations prior to that of the Br conservative tracer. Total Ce recovery from experiments using 0.45 μm filtered inlet solutions was only about 0.1%, and colloids of >0.45 μm constituted the majority of recovered Ce. About 1% of Ce was recovered when colloids of >0.45 μm were injected, indicating the enhanced mobility and recovery of Ce in the presence of bicarbonate.
胶体的迁移可能会促进放射性核素从近地表废物场和地质处置库中泄漏。在富含重碳酸盐的环境中，通过碳酸盐沉淀可以有利地形成固有胶体，并且它们的迁移可以通过断裂基岩得到增强。通过天然离散白垩岩裂缝，在人工雨水溶液中研究了 Ce(III)作为固有胶体的迁移性。结果表明，在不同的注入浓度（1 至 30mg/L 之间）下，几乎所有回收的 Ce 都以 >0.45μm 直径的固有胶体形式存在，包括那些入口溶液首先通过 0.45μm 过滤的实验。在所有实验中，这些固有胶体在 Br 保守示踪剂之前达到了其最大相对浓度。使用 0.45μm 过滤入口溶液进行实验时，总 Ce 的回收率仅约为 0.1%，而 >0.45μm 的胶体构成了回收 Ce 的大部分。当 >0.45μm 的胶体被注入时，回收了约 1%的 Ce，表明在存在重碳酸盐的情况下 Ce 的迁移性和回收率得到了增强。
