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

Abstract

• DVB-2C 8 VEIMBr has a great adsorption capacity of 313.28 mg g −1 for TcO 4 − . • It can remove 93% of TcO 4 − from the simulated Hanford LAW scrubber solution. • It shows excellent selectivity in the 6000 times SO 4 2− mixture solution. • It displays super stability being immersed in 3 M HCl or 2 M NaOH for 8 months. • DVB-2C 8 VEIMBr unfolds prominent regeneration ability after ten consecutive cycles. 99 Technetium ( 99 Tc) 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-2C 8 VEIMBr) was prepared for selective adsorption of TcO 4 − (ReO 4 − as an alternative for laboratory operation). It is manifested that DVB-2C 8 VEIMBr integrates high adsorption capacity (313.28 mg·g −1 ) and selectivity (90.68% in 6000 times excess of SO 4 2− ions). A real-scenario experiment exhibits DVB-2C 8 VEIMBr can remove up to 93% of TcO 4 − from the simulated Hanford LAW scrubber solution. More importantly, DVB-2C 8 VEIMBr 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 TcO 4 − or ReO 4 − immobilization process, which can be applied to capture these radioactive oxygen anions under high acid and high alkali conditions.