Chemical behavior of neptunium in the presence of technetium in nitric acid media

Zhou, Xianming; Guoan, Ye; Zhang, Hu; Li, Li; Luo, Fang; Meng, Zhen

doi:10.1515/ract-2014-2136

Cited by 21 publications

(8 citation statements)

References 12 publications

(16 reference statements)

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“…Tc(VII) complexes are volatile during nuclear waste vitrification process, producing problems for the off-gas system design 7 . Another serious issue associated with this radioisotope is its capability to greatly interface with the solvent extraction/back extraction process of uranium, neptunium, and plutonium through catalytic redox reactions, generating a notable barrier on the valence state control of these key components in the fuel cycle 8 , 9 . Therefore, it would be ideal that TcO 4 − can be separated at the first stage once used nuclear fuel rods are dissolved in highly concentrated nitric acid solutions even before the plutonium uranium redox extraction (PUREX) process.…”

Section: Introductionmentioning

confidence: 99%

99TcO4− remediation by a cationic polymeric network

et al. 2018

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Direct removal of 99TcO4− from the highly acidic solution of used nuclear fuel is highly beneficial for the recovery of uranium and plutonium and more importantly aids in the elimination of 99Tc discharge into the environment. However, this task represents a huge challenge given the combined extreme conditions of super acidity, high ionic strength, and strong radiation field. Here we overcome this challenge using a cationic polymeric network with significant TcO4− uptake capabilities in four aspects: the fastest sorption kinetics, the highest sorption capacity, the most promising uptake performance from highly acidic solutions, and excellent radiation-resistance and hydrolytic stability among all anion sorbent materials reported. In addition, this material is fully recyclable for multiple sorption/desorption trials, making it extremely attractive for waste partitioning and emergency remediation. The excellent TcO4− uptake capability is elucidated by X-ray absorption spectroscopy, solid-state NMR measurement, and density functional theory analysis on anion coordination and bonding.

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Section: Introductionmentioning

confidence: 99%

99TcO4− remediation by a cationic polymeric network

et al. 2018

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“…4 Moreover, the catalytic redox activity of 99 Tc can disrupt the control of oxidation states of other key components of spent nuclear fuel. 5,6 Separation of 99 TcO 4…”

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confidence: 99%

Radiation Controllable Synthesis of Robust Covalent Organic Framework Conjugates for Efficient Dynamic Column Extraction of 99TcO4−

Wang

Xie²,

Lan

et al. 2020

Chem

139

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Anion-scavenging materials tailored for 99 TcO 4 À trapping are urgently needed for both nuclear-related environmental remediation and management of spent nuclear fuel. For the first time, we report here an ultra-robust imidazolium-decorated covalent organic framework (COF) conjugate fabricated by an ionizing radiation strategy, for efficient capture of 99 TcO 4À . The charged imidazolium moieties are controllably anchored into the channel of the COF by simply adjusting the g-ray dose, thereby leading to tunable ReO 4 À uptake up to 952 mg g À1 with high selectivity and fast kinetics. More importantly, the high porosity and ultra-robust nanofiber structure of the COFs make them ideal packing materials for dynamic column experiments. >99.98% ReO 4 À /TcO 4 À can be efficiently separated and re-collected, even after four adsorptiondesorption cycles, ranking a new record of the elimination rate for ReO 4 À adsorption. The performance of these materials suggests attractive opportunities in practical applications for TcO 4 À removal from the environment and nuclear waste.

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“…The handling of 99 Tc during the nuclear waste vitrification process presents significant challenges due to the formation of volatile compounds such as Tc 2 O 7 , which escapes into the atmosphere . Another major problem that 99 Tc poses during the nuclear waste reprocessing process is its ability to interfere with the catalytic redox reactions that are used to control the valence state of uranium, neptunium, and plutonium during solvent extraction and the back‐extraction process in PUREX (plutonium uranium redox extraction) . After an accidental release, 99 TcO 4 − can transmit into the environment and infiltrate into the food chain, and thus presents a real threat to the contamination of ground water and the aquatic ecosystem, in which the contamination by 99 TcO 4 − may last for thousands of years due to its very long half‐life.…”

Section: Introductionmentioning

confidence: 99%

An Ultrafast Molecular‐Rotor‐Based Fluorescent Turn‐On Sensor for the Perrhenate Anion in Aqueous Solution

Desai

Singh

2019

Chemistry A European J

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Devising sensors for the perrhenate anion in aqueous media is extremely challenging, and has seldom been reported in the literature. Herein, we report a fluorescence turn‐on sensor for the perrhenate anion in aqueous media based on the aggregation‐induced emission of a popular ultrafast molecular rotor dye, Thioflavin‐T. The selective response towards the perrhenate anion has been rationalized in terms of matching water affinity, with the weakly hydrated perrhenate anion spontaneously forming a contact ion pair with the weakly hydrated ultrafast molecule‐rotor‐based organic cation, Thioflavin‐T, which in turn leads to an aggregate assembly that provides a fluorescence turn‐on response towards perrhenate. The sensing response of Thioflavin‐T has been found to be quite selective towards the perrhenate anion when tested against anions that are ubiquitously present in the environment, such as chloride, nitrate, and sulfate anions. The formation of self‐assembled Thioflavin‐T aggregates has also been investigated by time‐resolved emission and temperature‐dependent measurements.

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Chemical behavior of neptunium in the presence of technetium in nitric acid media

Cited by 21 publications

References 12 publications

99TcO4− remediation by a cationic polymeric network

99TcO4− remediation by a cationic polymeric network

Radiation Controllable Synthesis of Robust Covalent Organic Framework Conjugates for Efficient Dynamic Column Extraction of 99TcO4−

An Ultrafast Molecular‐Rotor‐Based Fluorescent Turn‐On Sensor for the Perrhenate Anion in Aqueous Solution

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