Selective removal of ReO4−/TcO4− by an imidazolyl-based polymer from 3 M HNO3 solution

The effective removal of 99TcO4− in the radioactive waste is very important and ReO4− was often used as the substitute of TcO4− for research. In this paper, an imidazolyl-based polymer TIB-TBPB was successfully synthesized and exhibited excellent adsorption performance for ReO4−. The results showed that the framework of TIB-TBPB is benzene-rich structure, which enhances its hydrophobicity and allows it to exhibit excellent thermal stability and acid-base stability. It could maintain the excellent recyclability even in 3 M HNO3. TIB-TBPB possessed the high capacity of 882 mg g−1 and the superb removal depth for ReO4− and TcO4− with Kd of 2.34 × 106 mL g−1 and 1.35 × 106 mL g−1, respectively. Furthermore, TIB-TBPB has the advantages of excellent selectivity, recyclability and could remove 65.7 % and 86.4 % of ReO4− from 3 M HNO3 and the Hanford LAW simulated nuclear waste, respectively. DFT calculation explained the selectivity of TIB-TBPB for ReO4− over NO3− and verified the experimental results. In a word, the excellent performance suggested TIB-TBPB would be a promising material for TcO4− /ReO4− removal.