A hydrophobic imidazolium cationic framework for selective adsorption of TcO4-/ReO4- from aqueous solutions

Traditional anion exchangers for TcO4- usually have low selectivity and adsorption capacity due to the lack of functional groups that interact strongly with TcO4-. Here, we report a three-dimensional imidazolium network IMI-P that exhibits high adsorption capacity, fast kinetics, and outstanding selectivity for ReO4-/TcO4- at pH 2-13. It can remove 90% of ReO4- in 30 s and 99% ReO4- in 10 min, which is significantly faster than most commercial materials. Besides, the maximum sorption capacity of IMI-P (792 mg ReO4-/g) is also higher than that of most commercial materials. IMI-P shows good TcO4- removal efficiencies for simulated wastewater, which can reach 91.5% and 98.4% at the solid-liquid ratio of 10 g L-1 and 50 g L-1, respectively. Compared with other Tc-adsorption polymers, IMI-P with a larger particle size (10-30 mu m) is more suitable for column chromatography separation. Therefore, IMI-P has important application potential in wastewater treatment in the nuclear industry. The adsorption mechanism of IMI-P and the interaction mode with ReO4- were also studied by IR, EDS, and XPS.