Silver oxide nanocrystals anchored on titanate nanotubes and nanofibers: promising candidates for entrapment of radioactive iodine anions

Abstract

Iodine radioisotopes are released into the environment by the nuclear industry and medical research institutions using radioactive materials. The ¹²⁹I⁻ anion is one of the more mobile radioactive species due to a long half-life, and it is a great challenge to design long-term management solutions for such radioactive waste. In this study, a new adsorbent structure with the potential to efficiently remove radioactive iodine anions (I⁻) from water is devised: silver oxide (Ag₂O) nanocrystals firmly anchored on the surface of titanate nanotubes and nanofibers via coherent interfaces between Ag₂O and titanate phases. I⁻ anions in fluids can easily access the Ag₂O nanocrystals and be efficiently trapped by forming AgI precipitate that firmly attaches to the adsorbent. Due to their one-dimensional morphology, the new adsorbents can be readily dispersed in liquids and easily separated after purification; and the adsorption beds loaded with the adsorbents can permit high flux. This significantly enhances the adsorption efficiency and reduces the separation costs. The proposed structure reveals a new direction in developing efficient adsorbents for the removal of radioactive anions from wastewater.