Facile synthesis of imidazolium cationic organic polymer with ultrafast ReO4−/99TcO4− removal under highly alkaline conditions

Abstract

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 (99Tc). 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 tri-imidazolium-charged monomer. Due to the synergetic effects of physical adsorption and ion exchange, PMV3m-Cl featured ultrafast 99TcO4− (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 (∼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 99TcO4− ions. Results of this study suggest PMV3m-Cl is a promising adsorbent for the removal of ReO4− and 99TcO4−, and provide valuable reference significance to design an alkaline resistant nuclear associated environmental remediation material.