Evaluation of an Imidazolium-Based Porous Organic Polymer as Radioactive Waste Scavenger.

ABSTRACT

99TcO4- is highly radioactive and hazardous to both the environment and public health, meanwhile, it is quite challenging to have it efficiently removed. Herein an imidazolium-based cationic porous polymer (ImPOP-1) is evaluated for removal of TcO4-, with nonradioactive ReO4- as the surrogate for experimental operation. It is demonstrated that ImPOP-1 is a rare example that can integrate high adsorption capacity (610 mg g-1), fast kinetics (93.3% in 30 s), and high selectivity (72.9% in 1000 times excess of SO42- ions) in one material. The distribution coefficient Kd is among the top up to 3.2 × 105 mL g-1. ImPOP-1 also displays high adsorption performance over a wide range of pH values, and removal efficiency up to 64.3% in a highly alkaline solution (3 M NaOH). Recyclability experiments demonstrate that ImPOP-1 can be reused at least four times. The ImPOP-1 also retains a consistent adsorption capacity up to 609 ± 6.1 mg g-1 between three different batches of samples. In addition, a real-scenario experiment shows that ImPOP-1 can remove 97.4% of ReO4- in a simulated Hanford LAW stream.