Ultra-efficient selective removal of 99TcO4–/ReO4– via self-polymerizing cationic organic polymer: Adsorption performance and mechanistic insight

The design of highly stable and efficient porous materials is crucial for physisorption-based separation of radioactive species ( 99 TcO 4 - /ReO 4 - ), serving as an alternative to current concentrate-storage-solidification treatment technologies. Herein, employing a covalent-ionic dual-crosslinking strategy with economical ionic compounds as reactive monomers, a novel cationic organic polymer (TJU-COP-1) was synthesized for the first time via facile radical polymerization for 99 TcO 4 - /ReO 4 - sequestration. TJU-COP-1 demonstrates exceptional adsorption capacity, kinetics and selectivity ( K d ) for 99 TcO 4 - /ReO 4 - (861.87 mg·g –1 , K d = 5.0 × 10 5 ml·g -1 ), achieving adsorption equilibrium within merely 1 min. Notably, TJU-COP-1 maintains adsorption efficiency as high as 96.25% after five adsorption-desorption cycles. The TJU-COP-1 showed high stability after acid (3 mol·L –1 HNO 3 ), alkali (3 mol·L –1 NaOH) and radiation (200 kGy 60 Co γ) treatment. More significantly, TJU-COP-1 demonstrated robust and promising removal performance in complex solution, achieving 98.55% efficiency for 99 TcO 4 - /ReO 4 - amid high concentrations of competing anions and an excellent 72.11% removal in simulated Hanford LAW waste solution. Combined experimental characterization and density functional theory theoretical validation confirmed that the adsorption mechanism involves a synergistic combination of electrostatic interactions and anion exchange. This study illustrates that TJU-COP-1 has great potential for practical application in the capture of 99 TcO 4 - /ReO 4 - , and provides a new approach to the design of high-performance adsorbents for the treatment of nuclear wastewater.