Facile Synthesis of Imidazolium Cationic Organic Polymer with Ultrafast ReO4−/99TcO4− Removal under Highly Alkaline Conditions

It is already known that nuclear power can reduce the greenhouse gas emissions, while must clear its release of a few but hazardous nuclear wastes. Therefore, there is an urgent need to rational design adsorption materials in order to excellent eliminate the radioactive contaminations, including the most potentially problematic technetium-99 (Tc-99). Herein, we present an easily synthetic approach to prepare a robust imidazolium-based cationic organic polymer (denoted as PMV3m-Cl) in a low-cost, through vinyl polymerization via a triimidazolium-charged monomer. Due to the synergetic effects of physical adsorption and ion exchange, PMV3m-Cl featured ultrafast 99TcO(4) (as well as its nonradioactive surrogate ReO4) adsorption kinetics, with the performance of 99 % removal within 1 min (at a relatively low solid-to-liquid ratio of 0.2 g/L). PMV3m-Cl also displayed high adsorption performance of ReO4 over a wide range of pH values, and remained up to 94 % removal rate after five cycles of adsorption/desorption. Even in extreme alkaline (3 M NaOH) solution, it can remain stable and rapidly remove ReO4, to reach the adsorption equilibriums at 30 s with a recorded removal efficiency of 79 %. Furthermore, it is noting that PMV3m-Cl enables to decontaminated low concentration (similar to 10 ppm) ReO4 contaminated potable water to residue of 7% within 1 min. The fast kinetics, excellent selectivity, and high uptake capacity (739 mg/g for ReO4) of PMV3m-Cl were attributed to that the framework is rich in positively charged imidazole segments exhibiting the strong electrostatic interactions and binding affinity with ReO4 and 99TcO(4) ions. Results of this study suggest PMV3m-Cl is a promising adsorbent for the removal of ReO4 and 99TcO(4), and provide valuable reference significance to design an alkaline resistant nuclear associated environmental remediation material.