Synthesis of imidazolium-based cationic organic polymer for highly efficient and selective removal of ReO4-/TcO4

Rational design of anion-scavenging materials with high selectivity and stability under high acid/base extreme conditions for removing 99TcO4- is still a significant challenge. Herein, we put forward an anion exchange strategy that utilized an imidazolium-based cationic organic polymer (named ImCOP) for efficient capture of perrhenate (ReO4- ), a surrogate for TcO4- with nonradioactive. ImCOP was synthesized via the quaternization reaction using tris (4-(1H-imidazol-1-yl) phenyl) amine, a tripodal flexible ligand, and 1,4-bis (bromomethyl) benzene to forming a semi-rigid structure. ImCOP exhibited high chemical stability even under 3 M HNO3 and 3 M NaOH, which was superior to those of most materials. Attributed to the charged imidazolium moieties and tertiary amine groups that produced rich adsorption sites, ImCOP can produce electrostatic interactions with ReO4-, thereby leading to a record uptake capability (1162 mg g-1) of ReO4- . Furthermore, ImCOP exhibited high selectivity for removing ReO4- in the presence of large excess of competitive anions, which was attributed to the hydrophobic surface of ImCOP. These excellent features endowed ImCOP successfully separated ReO4- from simulated Hanford waste with a high adsorption removal of 93.4%. The excellent performance suggested ImCOP would be a promising material for TcO4-/ReO4- removal, which provided a feasible pathway for designing a highefficiency and durable material for nuclear-related environmental remediation.

Automated summary

ImCOP, a cationic organic polymer synthesized through anion exchange strategy, exhibits excellent chemical stability and adsorption capability for capturing ReO4-. Its outstanding performance suggests ImCOP is a promising material for nuclear-related environmental remediation.