Highly efficient removal of radioactive iodine anions by nano silver modified activated carbon fiber

Abstract

Radioactive iodine anion wastewater is generated during the operation of nuclear facilities. Efficiently adsorbing and removing radioactive iodine is crucial for the sustainable development of nuclear energy. A potential adsorbent, nano silver-loaded activated carbon fiber (Ag@ACF), was prepared through hydrothermal synthesis and high-temperature vacuum reduction for the efficient removal of iodide anions. The as-prepared Ag@ACF composite has been comprehensively characterized, with silver nanoparticles uniformly distributed on the surface and pore walls of the Ag@ACF, enhancing the adsorption sites for iodine anions. The adsorption performance of Ag@ACF towards iodine anions was evaluated through column and batch experiments, varying silver concentration, adsorbent dosage, pH, contact time, and competing anions. Ag@ACF demonstrated high water stability and a low desorption rate of iodine anions. At a pH of 2, Ag@ACF exhibited a maximum adsorption capacity for iodine anions of 372 mg/g, surpassing most other adsorbents and showing promise for engineering applications. Adsorption kinetics and isotherm analysis indicated that the adsorption process of Ag@ACF primarily involved monolayer homogeneous chemisorption, resulting in the formation of stable AgI. These results suggest that Ag@ACF could serve as a potential adsorbent for removing iodine from radioactive wastewater.