Efficient and rapid elimination of 99TcO4−/ReO4− from medium-low level acid – Wastewater using anion exchange adsorbent

Abstract

Efficient removal of 99TcO4− from nuclear wastewater is of great urgency for both nuclear-related environmental remediation and the safe development of nuclear. In this work, an anion exchange adsorbent PP-g-GMA@EDA/SACl (PGESCl) based on polypropylene (PP) nonwovens is facilely prepared by radiation-induced grafting and chemical modification for 99TcO4− elimination. By the analogy of the ReO4−, the batch adsorption experiments at medium–low acidity show that PGESCl possessed fast adsorption kinetics (within 10 min), higher uptake capacity (251.13 mg/g for Re(VII)), and excellent selectivity in the presence of excessive competing anions such as NO3−, Cl− and SO42−. In the actual adsorption exploration of 99TcO4−, PGESCl still possesses a rapid adsorption process and excellent selectivity. X-ray photoelectron spectroscopy (XPS) and energy disperse spectroscopy (EDS) analyses reveal that anion exchange between the 99TcO4−/ReO4− in solution and the chloride ion in PGESCl plays a dominant role in the adsorption of 99TcO4−/ReO4−. The adsorbed 99TcO4−/ReO4− can be completely eluted by 1 mol/L HCl even after five adsorption–desorption cycles, indicating the excellent recyclability to capture 99TcO4−/ReO4−. The performance of PGESCl shows potential for effective 99TcO4− removal from radioactive nuclear wastewater.