Optimizing radionuclide sequestration in anion nanotraps with record pertechnetate sorption

Abstract

The elimination of specific contaminants from competitors poses a significant challenge. Rather than relying on a single direct interaction, the cooperation of multiple functionalities is an emerging strategy for adsorbents design to achieve the required affinity. Here, we describe that the interaction with the target species can be altered by modifying the local environment of the direct contact site, as demonstrated by manipulating the affinity of pyridinium-based anion nanotraps toward pertechnetate. Systematic control of the substituent effect allows the resulting anion nanotraps to combine multiple features, overcoming the long-term challenge of TcO 4 − segregation under extreme conditions of super acidity and basicity, strong irradiation field, and high ionic strength. The top material exhibits the highest sorption capacity together with record-high extraction efficiencies after a single treatment from conditions relevant to the used nuclear fuel (Hanford tank wastes, 95%) and legacy nuclear wastes (Savannah River Sites, 80%) among materials reported thus far.

Optimizing Strategy for Enhancing the Stability and 99TcO4– Sequestration of Poly(ionic liquids)@MOFs Composites

“…The distribution coefficient K d of bis -PC 2 (Cl)@MIL-101 is 3.3 × 10 6 mL g –1 , which is comparable to PQA- p N(Me) 2 Py-Cl (1.0 × 10 7 mL g –1 ) that represents the highest performance now. 58 To evaluate its real application for the instant radionuclide sequestration, a chromatographic column was fabricated with bis -PC 2 (Cl)@MIL-101 as the stationary phase. Notably, the water solution of ReO 4 – (188 ppm) could be successfully purified (95.4% removal), via simply passing it through the column under ambient pressure ( Figure S11 ).…”

99TcO4− removal from legacy defense nuclear waste by an alkaline-stable 2D cationic metal organic framework

“…A simulated SRS HLW Stream was prepared according to a reported protocol 22 and the molar concentration of the anions and molar ratio of each anion to that of 99 TcO 4 − are provided in Supplementary Table 10 . Measured quantities of the simulated SRS HLW Stream were pipetted into sample tubes containing a premeasured quantity of SCU-103 to provide solid/liquid ratios of 1, 5, 10, 20, and 40 g L −1 .…”

“…In addition, the sorption kinetics are rather slow and the elution is difficult owing to the strong affinity between resins and 99 TcO 4 − anion. The recently developed cationic COF 20 and CPN 21 , 22 overcome the shortcomings of the aforementioned materials, and possess remarkable advantages in 99 TcO 4 − separation under highly acidic conditions (e.g., 3 M nitric acid) that are found in used fuel reprocessing. However, these cationic materials exhibit notably poor alkaline stability because the cationic pyridine or imidazolium ring undergoes ring-opening reactions induced by nucleophilic attack from OH − in alkaline solutions.…”

Recent advances of sorption efficiency and mechanism of radionuclides on covalent organic frameworks materials

“…Sun等 [69] [72] ; (b) U(VI)在COF-TpDb-AO复合材料上的吸附动力学, 插图为U(VI)进入COF-TpDb-AO内孔壁 [69] (网络版彩图) 料, 如非晶多孔有机聚合物(52 mg/g) [71] . [78] ; (b) 分子动力学模拟TcO 4 − 与SCU-COF-1中Cl…”