Remarkable performance and physical origins of a multi-site functional material for 131I-ion exchange in nuclear medical wastewater.

Abstract

Rapid treatment of radioactive wastewater is critical for radiological medical diagnosis and therapy. An efficient yet cost-effective adsorbent capable of selectively removing radioactive nuclides is highly desired to meet the growing global demand for nuclear medicine. In this study, a simple one-step chemical grafting strategy was employed to directly synthesize a multi-site functional fiber containing quaternary ammonium chloride (-NR₃⁺Cl^-) and protonated secondary amine (-NH₂⁺-). This novel material exhibits a remarkably high ¹³¹I^- adsorption capacity, significantly outperforming commercial adsorbents. When applied to real hospital radioactive wastewater containing ¹³¹I, it reduces the total β-activity concentration to 4.63 Bq L^-1, well below the stringent global discharge standard of 10 Bq L^-1. Quantum-chemical studies elucidate the mechanism underlying its exceptional adsorption capacity and the physical origin of ion exchange. This work not only provides critical insights into the nature of high-performance ion exchange but also presents a promising practical approach for highly efficient capture of ¹³¹I from nuclear wastewater.