Key Laboratory of Green Chemistry and Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China.
Department of Environmental Engineering and Resource, Technical University of Denmark, Risø Campus, Roskilde DK-4000, Denmark.
Anal Chem. 2022 Aug 23;94(33):11582-11590. doi: 10.1021/acs.analchem.2c01954. Epub 2022 Aug 10.
Mo is an important radionuclide in view of radioactive waste repository because of its long half-life and high mobility in the environment. Mo decays by electron capture without any measurable gamma ray emission. The concentration of Mo in most of the radioactive waste is many orders of magnitude lower than the major activation product radionuclides, which makes the accurate determination of Mo a big challenge. A new analytical method for the determination of Mo in sulfuric acid media from nuclear power reactor was developed. Mo was separated from most of the radionuclides by cation exchange chromatography followed by the removal of sulfate by CaSO precipitation. A further purification of Mo, especially from anion species of Cr and Sb, was achieved by anion exchange chromatography and a short alumina column separation. The chemical yield of Mo in the entire separation procedure reached about 75%, and the decontamination factors for all potential interfering radionuclides were 1.5 × 10-1.6 × 10. The purified Mo was measured by liquid scintillation counting through counting its low-energy Auger electrons. A detection limit of 2 mBq/g for Mo in 50 g sample was achieved by this method, which enables the quantitative determination of Mo in most of the radioactive samples in the decommissioning waste and coolant water of nuclear power reactors. The developed method has been successfully applied to determine Mo in coolant water of nuclear power reactors, providing a robust analytical approach of Mo for the radiological characterization of radioactive wastes.
钼是放射性废物处置库中一种重要的放射性核素，因为它的半衰期长，在环境中的迁移性高。钼通过电子俘获衰变，没有任何可测量的伽马射线发射。在大多数放射性废物中，钼的浓度比主要活化产物放射性核素低几个数量级，这使得钼的准确测定成为一个巨大的挑战。开发了一种从核动力反应堆硫酸介质中测定钼的新分析方法。钼通过阳离子交换色谱与硫酸盐分离，然后用 CaSO4 沉淀去除。通过阴离子交换色谱和短氧化铝柱分离，进一步纯化钼，特别是从 Cr 和 Sb 的阴离子物种中分离。整个分离过程中钼的化学收率约为 75%，所有潜在干扰放射性核素的净化系数均为 1.5×10-1～1.6×10-1。通过液体闪烁计数测量纯化后的钼，通过测量其低能俄歇电子来计数。该方法实现了对 50g 样品中 2mBq/g 钼的检测限，可用于定量测定核动力反应堆退役废物和冷却水中的大多数放射性样品中的钼。该方法已成功应用于核动力反应堆冷却水中钼的测定，为放射性废物的放射性特征提供了一种可靠的钼分析方法。
