Highly efficient and selective capture of TcO4-or ReO4-by imidazolium-based ionic liquid polymers

99Technetium (99Tc) is one of the most dangerous radioactive isotopes in the legacy nuclear waste, and harmful to the environment and human health. Effectively removing it remains a long-term challenge. Herein a resin-like imidazolium-based ionic liquid polymer (DVB-2C8VEIMBr) was prepared for selective adsorption of TcO4- (ReO4as an alternative for laboratory operation). It is manifested that DVB-2C8VEIMBr integrates high adsorption capacity (313.28 mg.g- 1) and selectivity (90.68% in 6000 times excess of SO42- ions). A real-scenario experiment exhibits DVB-2C8VEIMBr can remove up to 93% of TcO4- from the simulated Hanford LAW scrubber solution. More importantly, DVB-2C8VEIMBr displays super acid and alkaline resistance and stability after immersing for 8 months under extreme conditions of 3 M HCl and 2 M NaOH. It can also effectively separate rhenium from molybdenum solution in the range of 3 M HCl - pH 2. Additionally, it still showed perfect regeneration performance after 10 cycles. In particular, this work demonstrates the feasibility of imidazolium-based ionic liquid adsorbents in the TcO4- or ReO4- immobilization process, which can be applied to capture these radioactive oxygen anions under high acid and high alkali conditions.

Automated summary

A resin-like imidazolium-based ionic liquid polymer was prepared for selective adsorption of 99Tc, demonstrating high adsorption capacity and selectivity. The polymer showed excellent removal efficiency of 99Tc from simulated waste solution and exhibited super acid and alkaline resistance and stability after long-term immersion.