A Novel Functionalized Ionic Liquid for Highly Selective Extraction of TcO₄^–

Abstract

Due to the highly acidic and high-salinity nature of the high-level radioactive waste liquid (HLLW), selective extraction of TcO4 – from HLLW remains to be a challenging task. Traditional anion exchangers show low selectivity and unsatisfactory extraction performance due to the lack of functional groups that can interact strongly with TcO4 –. In this work, a tailor-made binding site was constructed by decorating two acetamide functional groups on imidazolium cation to fabricate a new Tc separation material, which exhibits high selectivity. Unlike most reported Tc separation materials, which can only perform well under low acidic, neutral, or alkaline conditions, this material still has good extraction performance in highly acidic solutions. In the simulated high-level waste liquid of 3 M nitric acid, the extraction efficiency of 0.5 mol/L organic phase for Tc can reach 96.5% through the first-stage extraction. Our theoretical simulations suggest that ReO4 –/TcO4 – anions were adsorbed on the top of the imidazolium ring during the extraction process, with p−π and p–p interactions acting as the driving forces.

Ultraselective Extraction Reprocessing of 99TcO4–/ReO4– with a Promising Carbamic Acid Extractant System

“…The effects of acidity increase in the order of H 2 SO 4 < HCl < HNO 3 , and D2EHAG exhibits better extraction ability than M2EHAG and PLLAG. By comprehensive comparison with the extractants reported recently, most extractants have strict requirements on pH, but D2EHAG can have ultrahigh selectivity in a wide range of acidic pH values. ,, …”

“…99 Tc has high solubility in water, and radioactive waste liquid contains more competitive anions. The current removal technologies are mainly divided into two categories: extraction and adsorption; the extraction systems mainly include carbazole derivatives, 5 crown ethers, 6 eutectic solvents, 7 ionic liquids, 8 and amides. 9 These extractants may have high cost, complex synthesis, and low selectivity.…”

Highly Selective Adsorption of 99TcO4−/ReO4− by a Novel Polyamide-Functionalized Polyacrylamide Polymer Material

“…In an alkaline environment, OH − in the aqueous phase will be attracted by protonated -NH, which occupies the adsorption sites, resulting in a decline in the adsorption effect of ReO 4 − . Compared to amino triazole-modified microcrystalline cellulose microsphere and ionic liquid-MIMDIDOA, p-(Amide)-PAM can efficiently remove ReO 4 − over a wide range of pH values [ 42 , 45 ].…”